diff --git a/server/domain/src/form.rs b/server/domain/src/form.rs
index c446ac88..4db0f5c4 100644
--- a/server/domain/src/form.rs
+++ b/server/domain/src/form.rs
@@ -1 +1,5 @@
+pub mod answer;
+pub mod comment;
+pub mod message;
 pub mod models;
+pub mod question;
diff --git a/server/domain/src/form/answer.rs b/server/domain/src/form/answer.rs
new file mode 100644
index 00000000..e072fd8b
--- /dev/null
+++ b/server/domain/src/form/answer.rs
@@ -0,0 +1 @@
+pub mod models;
diff --git a/server/domain/src/form/answer/models.rs b/server/domain/src/form/answer/models.rs
new file mode 100644
index 00000000..cf929c00
--- /dev/null
+++ b/server/domain/src/form/answer/models.rs
@@ -0,0 +1,37 @@
+use chrono::{DateTime, Utc};
+#[cfg(test)]
+use proptest_derive::Arbitrary;
+use serde::{Deserialize, Serialize};
+
+use crate::{
+    form::{models::FormId, question::models::QuestionId},
+    user::models::User,
+};
+
+pub type AnswerId = types::IntegerId<FormAnswer>;
+
+#[derive(Serialize, Deserialize, PartialEq, Debug)]
+pub struct FormAnswer {
+    pub id: AnswerId,
+    pub user: User,
+    pub timestamp: DateTime<Utc>,
+    pub form_id: FormId,
+    pub title: Option<String>,
+}
+
+#[derive(Serialize, Deserialize, Clone, PartialEq, Debug)]
+pub struct FormAnswerContent {
+    pub answer_id: AnswerId,
+    pub question_id: QuestionId,
+    pub answer: String,
+}
+
+pub type AnswerLabelId = types::IntegerId<AnswerLabel>;
+
+#[cfg_attr(test, derive(Arbitrary))]
+#[derive(Serialize, Deserialize, Debug, PartialEq)]
+pub struct AnswerLabel {
+    pub id: AnswerLabelId,
+    pub answer_id: AnswerId,
+    pub name: String,
+}
diff --git a/server/domain/src/form/comment.rs b/server/domain/src/form/comment.rs
new file mode 100644
index 00000000..e072fd8b
--- /dev/null
+++ b/server/domain/src/form/comment.rs
@@ -0,0 +1 @@
+pub mod models;
diff --git a/server/domain/src/form/comment/models.rs b/server/domain/src/form/comment/models.rs
new file mode 100644
index 00000000..5bd21d79
--- /dev/null
+++ b/server/domain/src/form/comment/models.rs
@@ -0,0 +1,15 @@
+use chrono::{DateTime, Utc};
+use serde::{Deserialize, Serialize};
+
+use crate::{form::answer::models::AnswerId, user::models::User};
+
+pub type CommentId = types::IntegerId<Comment>;
+
+#[derive(Serialize, Deserialize, Debug, PartialEq)]
+pub struct Comment {
+    pub answer_id: AnswerId,
+    pub comment_id: CommentId,
+    pub content: String,
+    pub timestamp: DateTime<Utc>,
+    pub commented_by: User,
+}
diff --git a/server/domain/src/form/message.rs b/server/domain/src/form/message.rs
new file mode 100644
index 00000000..e072fd8b
--- /dev/null
+++ b/server/domain/src/form/message.rs
@@ -0,0 +1 @@
+pub mod models;
diff --git a/server/domain/src/form/message/models.rs b/server/domain/src/form/message/models.rs
new file mode 100644
index 00000000..264fb2ee
--- /dev/null
+++ b/server/domain/src/form/message/models.rs
@@ -0,0 +1,372 @@
+use chrono::{DateTime, Utc};
+use derive_getters::Getters;
+use errors::domain::DomainError;
+
+use crate::{
+    form::answer::models::FormAnswer,
+    types::authorization_guard::AuthorizationGuardDefinitions,
+    user::models::{Role::Administrator, User},
+};
+
+pub type MessageId = types::Id<Message>;
+
+#[derive(Getters, PartialEq, Debug)]
+pub struct Message {
+    id: MessageId,
+    related_answer: FormAnswer,
+    sender: User,
+    body: String,
+    timestamp: DateTime<Utc>,
+}
+
+impl AuthorizationGuardDefinitions<Message> for Message {
+    /// [`Message`] の作成権限があるかどうかを判定します。
+    ///
+    /// 作成権限は以下の条件のどちらかを満たしている場合に与えられます。
+    /// - [`actor`] が [`Administrator`] である場合
+    /// - [`actor`] が関連する回答の回答者である場合
+    ///
+    /// # Examples
+    /// ```
+    /// use domain::{
+    ///     form::{answer::models::FormAnswer, message::models::Message},
+    ///     types::authorization_guard::AuthorizationGuardDefinitions,
+    ///     user::models::{Role, User},
+    /// };
+    /// use uuid::Uuid;
+    ///
+    /// let respondent = User {
+    ///     name: "respondent".to_string(),
+    ///     id: Uuid::new_v4(),
+    ///     role: Role::StandardUser,
+    /// };
+    ///
+    /// let related_answer = FormAnswer {
+    ///     id: Default::default(),
+    ///     user: respondent.to_owned(),
+    ///     timestamp: Default::default(),
+    ///     form_id: Default::default(),
+    ///     title: Default::default(),
+    /// };
+    ///
+    /// let message = Message::try_new(
+    ///     related_answer,
+    ///     respondent.to_owned(),
+    ///     "test message".to_string(),
+    /// )
+    /// .unwrap();
+    ///
+    /// let administrator = User {
+    ///     name: "administrator".to_string(),
+    ///     id: Uuid::new_v4(),
+    ///     role: Role::Administrator,
+    /// };
+    ///
+    /// let unrelated_standard_user = User {
+    ///     name: "unrelated_user".to_string(),
+    ///     id: Uuid::new_v4(),
+    ///     role: Role::StandardUser,
+    /// };
+    ///
+    /// assert!(message.can_create(&respondent));
+    /// assert!(message.can_create(&administrator));
+    /// assert!(!message.can_create(&unrelated_standard_user));
+    /// ```
+    fn can_create(&self, actor: &User) -> bool {
+        actor.role == Administrator
+            || (actor.id == self.sender.id && self.related_answer.user.id == self.sender.id)
+    }
+
+    /// [`Message`] の読み取り権限があるかどうかを判定します。
+    ///
+    /// 読み取り権限は以下の条件のどちらかを満たしている場合に与えられます。
+    /// - [`actor`] が [`Administrator`] である場合
+    /// - [`actor`] が関連する回答の回答者である場合
+    ///
+    /// # Examples
+    /// ```
+    /// use domain::{
+    ///     form::{answer::models::FormAnswer, message::models::Message},
+    ///     types::authorization_guard::AuthorizationGuardDefinitions,
+    ///     user::models::{Role, User},
+    /// };
+    /// use uuid::Uuid;
+    ///
+    /// let respondent = User {
+    ///     name: "respondent".to_string(),
+    ///     id: Uuid::new_v4(),
+    ///     role: Role::StandardUser,
+    /// };
+    ///
+    /// let related_answer = FormAnswer {
+    ///     id: Default::default(),
+    ///     user: respondent.to_owned(),
+    ///     timestamp: Default::default(),
+    ///     form_id: Default::default(),
+    ///     title: Default::default(),
+    /// };
+    ///
+    /// let message = Message::try_new(
+    ///     related_answer,
+    ///     respondent.to_owned(),
+    ///     "test message".to_string(),
+    /// )
+    /// .unwrap();
+    ///
+    /// let administrator = User {
+    ///     name: "administrator".to_string(),
+    ///     id: Uuid::new_v4(),
+    ///     role: Role::Administrator,
+    /// };
+    ///
+    /// let unrelated_standard_user = User {
+    ///     name: "unrelated_user".to_string(),
+    ///     id: Uuid::new_v4(),
+    ///     role: Role::StandardUser,
+    /// };
+    ///
+    /// assert!(message.can_read(&respondent));
+    /// assert!(message.can_read(&administrator));
+    /// assert!(!message.can_read(&unrelated_standard_user));
+    /// ```
+    fn can_read(&self, actor: &User) -> bool {
+        actor.role == Administrator || self.related_answer.user.id == actor.id
+    }
+
+    /// [`Message`] の更新権限があるかどうかを判定します。
+    ///
+    /// 更新権限は以下の条件を満たしている場合に与えられます。
+    /// - [`actor`] がメッセージの送信者の場合
+    ///
+    /// [`actor`] が [`Administrator`] である場合に更新権限が与えられないのは、
+    /// メッセージの送信者が意図しない更新が行われることを防ぐためです。
+    ///
+    /// # Examples
+    /// ```
+    /// use domain::{
+    ///     form::{answer::models::FormAnswer, message::models::Message},
+    ///     types::authorization_guard::AuthorizationGuardDefinitions,
+    ///     user::models::{Role, User},
+    /// };
+    /// use uuid::Uuid;
+    ///
+    /// let respondent = User {
+    ///     name: "respondent".to_string(),
+    ///     id: Uuid::new_v4(),
+    ///     role: Role::StandardUser,
+    /// };
+    ///
+    /// let related_answer = FormAnswer {
+    ///     id: Default::default(),
+    ///     user: respondent.to_owned(),
+    ///     timestamp: Default::default(),
+    ///     form_id: Default::default(),
+    ///     title: Default::default(),
+    /// };
+    ///
+    /// let message = Message::try_new(
+    ///     related_answer,
+    ///     respondent.to_owned(),
+    ///     "test message".to_string(),
+    /// )
+    /// .unwrap();
+    ///
+    /// let administrator = User {
+    ///     name: "administrator".to_string(),
+    ///     id: Uuid::new_v4(),
+    ///     role: Role::Administrator,
+    /// };
+    ///
+    /// let unrelated_standard_user = User {
+    ///     name: "unrelated_user".to_string(),
+    ///     id: Uuid::new_v4(),
+    ///     role: Role::StandardUser,
+    /// };
+    ///
+    /// assert!(message.can_update(&respondent));
+    /// assert!(!message.can_update(&administrator));
+    /// assert!(!message.can_update(&unrelated_standard_user));
+    /// ```
+    fn can_update(&self, actor: &User) -> bool {
+        self.sender.id == actor.id
+    }
+
+    /// [`Message`] の削除権限があるかどうかを判定します。
+    ///
+    /// 削除権限は以下の条件を満たしている場合に与えられます。
+    /// - [`actor`] がメッセージの送信者の場合
+    ///
+    /// [`actor`] が [`Administrator`] である場合に更新権限が与えられないのは、
+    /// メッセージの送信者が意図しない削除(メッセージ内容の改変)が行われることを防ぐためです。
+    ///
+    /// # Examples
+    /// ```
+    /// use domain::{
+    ///     form::{answer::models::FormAnswer, message::models::Message},
+    ///     types::authorization_guard::AuthorizationGuardDefinitions,
+    ///     user::models::{Role, User},
+    /// };
+    /// use uuid::Uuid;
+    ///
+    /// let respondent = User {
+    ///     name: "respondent".to_string(),
+    ///     id: Uuid::new_v4(),
+    ///     role: Role::StandardUser,
+    /// };
+    ///
+    /// let related_answer = FormAnswer {
+    ///     id: Default::default(),
+    ///     user: respondent.to_owned(),
+    ///     timestamp: Default::default(),
+    ///     form_id: Default::default(),
+    ///     title: Default::default(),
+    /// };
+    ///
+    /// let message = Message::try_new(
+    ///     related_answer,
+    ///     respondent.to_owned(),
+    ///     "test message".to_string(),
+    /// )
+    /// .unwrap();
+    ///
+    /// let administrator = User {
+    ///     name: "administrator".to_string(),
+    ///     id: Uuid::new_v4(),
+    ///     role: Role::Administrator,
+    /// };
+    ///
+    /// let unrelated_standard_user = User {
+    ///     name: "unrelated_user".to_string(),
+    ///     id: Uuid::new_v4(),
+    ///     role: Role::StandardUser,
+    /// };
+    ///
+    /// assert!(message.can_delete(&respondent));
+    /// assert!(!message.can_delete(&administrator));
+    /// assert!(!message.can_delete(&unrelated_standard_user));
+    /// ```
+    fn can_delete(&self, actor: &User) -> bool {
+        self.sender.id == actor.id
+    }
+}
+
+impl Message {
+    /// [`Message`] の生成を試みます。
+    ///
+    /// 以下の場合に失敗します。
+    /// - [`body`] が空文字列の場合
+    ///
+    /// # Examples
+    /// ```
+    /// use domain::{
+    ///     form::{answer::models::FormAnswer, message::models::Message},
+    ///     user::models::{Role, User},
+    /// };
+    /// use uuid::Uuid;
+    ///
+    /// let user = User {
+    ///     name: "user".to_string(),
+    ///     id: Uuid::new_v4(),
+    ///     role: Role::StandardUser,
+    /// };
+    ///
+    /// let related_answer = FormAnswer {
+    ///     id: 1.into(),
+    ///     user: user.to_owned(),
+    ///     timestamp: Default::default(),
+    ///     form_id: Default::default(),
+    ///     title: Default::default(),
+    /// };
+    ///
+    /// let success_message =
+    ///     Message::try_new(related_answer, user.to_owned(), "test message".to_string());
+    ///
+    /// let related_answer = FormAnswer {
+    ///     id: 1.into(),
+    ///     user: user.to_owned(),
+    ///     timestamp: Default::default(),
+    ///     form_id: Default::default(),
+    ///     title: Default::default(),
+    /// };
+    /// let message_with_empty_body = Message::try_new(related_answer, user, "".to_string());
+    ///
+    /// assert!(success_message.is_ok());
+    /// assert!(message_with_empty_body.is_err());
+    /// ```
+    pub fn try_new(
+        related_answer: FormAnswer,
+        sender: User,
+        body: String,
+    ) -> Result<Self, DomainError> {
+        if body.is_empty() {
+            return Err(DomainError::EmptyMessageBody);
+        }
+
+        Ok(Self {
+            id: MessageId::new(),
+            related_answer,
+            sender,
+            body,
+            timestamp: Utc::now(),
+        })
+    }
+
+    /// [`Message`] の各フィールドの値を受け取り、[`Message`] を生成します。
+    ///
+    /// # Examples
+    /// ```
+    /// use chrono::{DateTime, Utc};
+    /// use domain::{
+    ///     form::{
+    ///         answer::models::FormAnswer,
+    ///         message::models::{Message, MessageId},
+    ///     },
+    ///     user::models::{Role, User},
+    /// };
+    /// use uuid::Uuid;
+    ///
+    /// let user = User {
+    ///     name: "user".to_string(),
+    ///     id: Uuid::new_v4(),
+    ///     role: Role::StandardUser,
+    /// };
+    ///
+    /// let related_answer = FormAnswer {
+    ///     id: 1.into(),
+    ///     user: user.to_owned(),
+    ///     timestamp: Utc::now(),
+    ///     form_id: Default::default(),
+    ///     title: Default::default(),
+    /// };
+    ///
+    /// unsafe {
+    ///     let message = Message::from_raw_parts(
+    ///         MessageId::new(),
+    ///         related_answer,
+    ///         user,
+    ///         "test message".to_string(),
+    ///         Utc::now(),
+    ///     );
+    /// }
+    /// ```
+    ///
+    /// # Safety
+    /// この関数は [`Message`] のバリデーションをスキップするため、
+    /// データベースからすでにバリデーションされているデータを読み出すときなど、
+    /// データの信頼性が保証されている場合にのみ使用してください。
+    pub unsafe fn from_raw_parts(
+        id: MessageId,
+        related_answer: FormAnswer,
+        sender: User,
+        body: String,
+        timestamp: DateTime<Utc>,
+    ) -> Self {
+        Self {
+            id,
+            related_answer,
+            sender,
+            body,
+            timestamp,
+        }
+    }
+}
diff --git a/server/domain/src/form/models.rs b/server/domain/src/form/models.rs
index 159401f8..cf6400c9 100644
--- a/server/domain/src/form/models.rs
+++ b/server/domain/src/form/models.rs
@@ -1,6 +1,6 @@
 use chrono::{DateTime, Utc};
 #[cfg(test)]
-use common::test_utils::{arbitrary_date_time, arbitrary_opt_date_time, arbitrary_with_size};
+use common::test_utils::{arbitrary_date_time, arbitrary_opt_date_time};
 use derive_getters::Getters;
 use deriving_via::DerivingVia;
 use errors::domain::{DomainError, DomainError::EmptyValue};
@@ -434,124 +434,6 @@ impl AuthorizationGuardDefinitions<Form> for Form {
     }
 }
 
-pub type QuestionId = types::IntegerId<Question>;
-
-#[cfg_attr(test, derive(Arbitrary))]
-#[derive(Serialize, Deserialize, Clone, Getters, Debug, PartialEq)]
-pub struct Question {
-    #[serde(default)]
-    pub id: Option<QuestionId>,
-    pub form_id: FormId,
-    pub title: String,
-    pub description: Option<String>,
-    pub question_type: QuestionType,
-    #[cfg_attr(test, proptest(strategy = "arbitrary_with_size(1..100)"))]
-    #[serde(default)]
-    pub choices: Vec<String>,
-    pub is_required: bool,
-}
-
-impl Question {
-    pub fn new(
-        id: Option<QuestionId>,
-        form_id: FormId,
-        title: String,
-        description: Option<String>,
-        question_type: QuestionType,
-        choices: Vec<String>,
-        is_required: bool,
-    ) -> Self {
-        Self {
-            id,
-            form_id,
-            title,
-            description,
-            question_type,
-            choices,
-            is_required,
-        }
-    }
-
-    pub fn from_raw_parts(
-        id: Option<QuestionId>,
-        form_id: FormId,
-        title: String,
-        description: Option<String>,
-        question_type: QuestionType,
-        choices: Vec<String>,
-        is_required: bool,
-    ) -> Self {
-        Self {
-            id,
-            form_id,
-            title,
-            description,
-            question_type,
-            choices,
-            is_required,
-        }
-    }
-}
-
-#[cfg_attr(test, derive(Arbitrary))]
-#[derive(
-    Debug, Serialize, Deserialize, Clone, Copy, EnumString, PartialOrd, PartialEq, Display,
-)]
-#[strum(ascii_case_insensitive)]
-pub enum QuestionType {
-    TEXT,
-    SINGLE,
-    MULTIPLE,
-}
-
-impl TryFrom<String> for QuestionType {
-    type Error = DomainError;
-
-    fn try_from(value: String) -> Result<Self, Self::Error> {
-        use std::str::FromStr;
-        Self::from_str(&value).map_err(Into::into)
-    }
-}
-
-pub type AnswerId = types::IntegerId<FormAnswer>;
-
-#[derive(Serialize, Deserialize, PartialEq, Debug)]
-pub struct FormAnswer {
-    pub id: AnswerId,
-    pub user: User,
-    pub timestamp: DateTime<Utc>,
-    pub form_id: FormId,
-    pub title: Option<String>,
-}
-
-#[derive(Serialize, Deserialize, Clone, PartialEq, Debug)]
-pub struct FormAnswerContent {
-    pub answer_id: AnswerId,
-    pub question_id: QuestionId,
-    pub answer: String,
-}
-
-pub type CommentId = types::IntegerId<Comment>;
-
-#[derive(Serialize, Deserialize, Debug, PartialEq)]
-pub struct Comment {
-    pub answer_id: AnswerId,
-    pub comment_id: CommentId,
-    pub content: String,
-    pub timestamp: DateTime<Utc>,
-    pub commented_by: User,
-}
-
-pub type AnswerLabelId = types::IntegerId<AnswerLabel>;
-
-#[cfg_attr(test, derive(Arbitrary))]
-#[derive(Serialize, Deserialize, Debug, PartialEq)]
-pub struct AnswerLabel {
-    pub id: AnswerLabelId,
-    pub answer_id: AnswerId,
-    pub name: String,
-}
-
 pub type LabelId = types::IntegerId<Label>;
 
 #[cfg_attr(test, derive(Arbitrary))]
@@ -561,371 +443,12 @@ pub struct Label {
     pub name: String,
 }
 
-pub type MessageId = types::Id<Message>;
-
-#[derive(Getters, PartialEq, Debug)]
-pub struct Message {
-    id: MessageId,
-    related_answer: FormAnswer,
-    sender: User,
-    body: String,
-    timestamp: DateTime<Utc>,
-}
-
-impl AuthorizationGuardDefinitions<Message> for Message {
-    /// [`Message`] の作成権限があるかどうかを判定します。
-    ///
-    /// 作成権限は以下の条件のどちらかを満たしている場合に与えられます。
-    /// - [`actor`] が [`Administrator`] である場合
-    /// - [`actor`] が関連する回答の回答者である場合
-    ///
-    /// # Examples
-    /// ```
-    /// use domain::{
-    ///     form::models::{FormAnswer, Message},
-    ///     types::authorization_guard::AuthorizationGuardDefinitions,
-    ///     user::models::{Role, User},
-    /// };
-    /// use uuid::Uuid;
-    ///
-    /// let respondent = User {
-    ///     name: "respondent".to_string(),
-    ///     id: Uuid::new_v4(),
-    ///     role: Role::StandardUser,
-    /// };
-    ///
-    /// let related_answer = FormAnswer {
-    ///     id: Default::default(),
-    ///     user: respondent.to_owned(),
-    ///     timestamp: Default::default(),
-    ///     form_id: Default::default(),
-    ///     title: Default::default(),
-    /// };
-    ///
-    /// let message = Message::try_new(
-    ///     related_answer,
-    ///     respondent.to_owned(),
-    ///     "test message".to_string(),
-    /// )
-    /// .unwrap();
-    ///
-    /// let administrator = User {
-    ///     name: "administrator".to_string(),
-    ///     id: Uuid::new_v4(),
-    ///     role: Role::Administrator,
-    /// };
-    ///
-    /// let unrelated_standard_user = User {
-    ///     name: "unrelated_user".to_string(),
-    ///     id: Uuid::new_v4(),
-    ///     role: Role::StandardUser,
-    /// };
-    ///
-    /// assert!(message.can_create(&respondent));
-    /// assert!(message.can_create(&administrator));
-    /// assert!(!message.can_create(&unrelated_standard_user));
-    /// ```
-    fn can_create(&self, actor: &User) -> bool {
-        actor.role == Administrator
-            || (actor.id == self.sender.id && self.related_answer.user.id == self.sender.id)
-    }
-
-    /// [`Message`] の読み取り権限があるかどうかを判定します。
-    ///
-    /// 読み取り権限は以下の条件のどちらかを満たしている場合に与えられます。
-    /// - [`actor`] が [`Administrator`] である場合
-    /// - [`actor`] が関連する回答の回答者である場合
-    ///
-    /// # Examples
-    /// ```
-    /// use domain::{
-    ///     form::models::{FormAnswer, Message},
-    ///     types::authorization_guard::AuthorizationGuardDefinitions,
-    ///     user::models::{Role, User},
-    /// };
-    /// use uuid::Uuid;
-    ///
-    /// let respondent = User {
-    ///     name: "respondent".to_string(),
-    ///     id: Uuid::new_v4(),
-    ///     role: Role::StandardUser,
-    /// };
-    ///
-    /// let related_answer = FormAnswer {
-    ///     id: Default::default(),
-    ///     user: respondent.to_owned(),
-    ///     timestamp: Default::default(),
-    ///     form_id: Default::default(),
-    ///     title: Default::default(),
-    /// };
-    ///
-    /// let message = Message::try_new(
-    ///     related_answer,
-    ///     respondent.to_owned(),
-    ///     "test message".to_string(),
-    /// )
-    /// .unwrap();
-    ///
-    /// let administrator = User {
-    ///     name: "administrator".to_string(),
-    ///     id: Uuid::new_v4(),
-    ///     role: Role::Administrator,
-    /// };
-    ///
-    /// let unrelated_standard_user = User {
-    ///     name: "unrelated_user".to_string(),
-    ///     id: Uuid::new_v4(),
-    ///     role: Role::StandardUser,
-    /// };
-    ///
-    /// assert!(message.can_read(&respondent));
-    /// assert!(message.can_read(&administrator));
-    /// assert!(!message.can_read(&unrelated_standard_user));
-    /// ```
-    fn can_read(&self, actor: &User) -> bool {
-        actor.role == Administrator || self.related_answer.user.id == actor.id
-    }
-
-    /// [`Message`] の更新権限があるかどうかを判定します。
-    ///
-    /// 更新権限は以下の条件を満たしている場合に与えられます。
-    /// - [`actor`] がメッセージの送信者の場合
-    ///
-    /// [`actor`] が [`Administrator`] である場合に更新権限が与えられないのは、
-    /// メッセージの送信者が意図しない更新が行われることを防ぐためです。
-    ///
-    /// # Examples
-    /// ```
-    /// use domain::{
-    ///     form::models::{FormAnswer, Message},
-    ///     types::authorization_guard::AuthorizationGuardDefinitions,
-    ///     user::models::{Role, User},
-    /// };
-    /// use uuid::Uuid;
-    ///
-    /// let respondent = User {
-    ///     name: "respondent".to_string(),
-    ///     id: Uuid::new_v4(),
-    ///     role: Role::StandardUser,
-    /// };
-    ///
-    /// let related_answer = FormAnswer {
-    ///     id: Default::default(),
-    ///     user: respondent.to_owned(),
-    ///     timestamp: Default::default(),
-    ///     form_id: Default::default(),
-    ///     title: Default::default(),
-    /// };
-    ///
-    /// let message = Message::try_new(
-    ///     related_answer,
-    ///     respondent.to_owned(),
-    ///     "test message".to_string(),
-    /// )
-    /// .unwrap();
-    ///
-    /// let administrator = User {
-    ///     name: "administrator".to_string(),
-    ///     id: Uuid::new_v4(),
-    ///     role: Role::Administrator,
-    /// };
-    ///
-    /// let unrelated_standard_user = User {
-    ///     name: "unrelated_user".to_string(),
-    ///     id: Uuid::new_v4(),
-    ///     role: Role::StandardUser,
-    /// };
-    ///
-    /// assert!(message.can_update(&respondent));
-    /// assert!(!message.can_update(&administrator));
-    /// assert!(!message.can_update(&unrelated_standard_user));
-    /// ```
-    fn can_update(&self, actor: &User) -> bool {
-        self.sender.id == actor.id
-    }
-
-    /// [`Message`] の削除権限があるかどうかを判定します。
-    ///
-    /// 削除権限は以下の条件を満たしている場合に与えられます。
-    /// - [`actor`] がメッセージの送信者の場合
-    ///
-    /// [`actor`] が [`Administrator`] である場合に更新権限が与えられないのは、
-    /// メッセージの送信者が意図しない削除(メッセージ内容の改変)が行われることを防ぐためです。
-    ///
-    /// # Examples
-    /// ```
-    /// use domain::{
-    ///     form::models::{FormAnswer, Message},
-    ///     types::authorization_guard::AuthorizationGuardDefinitions,
-    ///     user::models::{Role, User},
-    /// };
-    /// use uuid::Uuid;
-    ///
-    /// let respondent = User {
-    ///     name: "respondent".to_string(),
-    ///     id: Uuid::new_v4(),
-    ///     role: Role::StandardUser,
-    /// };
-    ///
-    /// let related_answer = FormAnswer {
-    ///     id: Default::default(),
-    ///     user: respondent.to_owned(),
-    ///     timestamp: Default::default(),
-    ///     form_id: Default::default(),
-    ///     title: Default::default(),
-    /// };
-    ///
-    /// let message = Message::try_new(
-    ///     related_answer,
-    ///     respondent.to_owned(),
-    ///     "test message".to_string(),
-    /// )
-    /// .unwrap();
-    ///
-    /// let administrator = User {
-    ///     name: "administrator".to_string(),
-    ///     id: Uuid::new_v4(),
-    ///     role: Role::Administrator,
-    /// };
-    ///
-    /// let unrelated_standard_user = User {
-    ///     name: "unrelated_user".to_string(),
-    ///     id: Uuid::new_v4(),
-    ///     role: Role::StandardUser,
-    /// };
-    ///
-    /// assert!(message.can_delete(&respondent));
-    /// assert!(!message.can_delete(&administrator));
-    /// assert!(!message.can_delete(&unrelated_standard_user));
-    /// ```
-    fn can_delete(&self, actor: &User) -> bool {
-        self.sender.id == actor.id
-    }
-}
-
-impl Message {
-    /// [`Message`] の生成を試みます。
-    ///
-    /// 以下の場合に失敗します。
-    /// - [`body`] が空文字列の場合
-    ///
-    /// # Examples
-    /// ```
-    /// use domain::{
-    ///     form::models::{FormAnswer, Message},
-    ///     user::models::{Role, User},
-    /// };
-    /// use uuid::Uuid;
-    ///
-    /// let user = User {
-    ///     name: "user".to_string(),
-    ///     id: Uuid::new_v4(),
-    ///     role: Role::StandardUser,
-    /// };
-    ///
-    /// let related_answer = FormAnswer {
-    ///     id: 1.into(),
-    ///     user: user.to_owned(),
-    ///     timestamp: Default::default(),
-    ///     form_id: Default::default(),
-    ///     title: Default::default(),
-    /// };
-    ///
-    /// let success_message =
-    ///     Message::try_new(related_answer, user.to_owned(), "test message".to_string());
-    ///
-    /// let related_answer = FormAnswer {
-    ///     id: 1.into(),
-    ///     user: user.to_owned(),
-    ///     timestamp: Default::default(),
-    ///     form_id: Default::default(),
-    ///     title: Default::default(),
-    /// };
-    /// let message_with_empty_body = Message::try_new(related_answer, user, "".to_string());
-    ///
-    /// assert!(success_message.is_ok());
-    /// assert!(message_with_empty_body.is_err());
-    /// ```
-    pub fn try_new(
-        related_answer: FormAnswer,
-        sender: User,
-        body: String,
-    ) -> Result<Self, DomainError> {
-        if body.is_empty() {
-            return Err(DomainError::EmptyMessageBody);
-        }
-
-        Ok(Self {
-            id: MessageId::new(),
-            related_answer,
-            sender,
-            body,
-            timestamp: Utc::now(),
-        })
-    }
-
-    /// [`Message`] の各フィールドの値を受け取り、[`Message`] を生成します。
-    ///
-    /// # Examples
-    /// ```
-    /// use chrono::{DateTime, Utc};
-    /// use domain::{
-    ///     form::models::{AnswerId, FormAnswer, Message, MessageId},
-    ///     user::models::{Role, User},
-    /// };
-    /// use uuid::Uuid;
-    ///
-    /// let user = User {
-    ///     name: "user".to_string(),
-    ///     id: Uuid::new_v4(),
-    ///     role: Role::StandardUser,
-    /// };
-    ///
-    /// let related_answer = FormAnswer {
-    ///     id: 1.into(),
-    ///     user: user.to_owned(),
-    ///     timestamp: Utc::now(),
-    ///     form_id: Default::default(),
-    ///     title: Default::default(),
-    /// };
-    ///
-    /// unsafe {
-    ///     let message = Message::from_raw_parts(
-    ///         MessageId::new(),
-    ///         related_answer,
-    ///         user,
-    ///         "test message".to_string(),
-    ///         Utc::now(),
-    ///     );
-    /// }
-    /// ```
-    ///
-    /// # Safety
-    /// この関数は [`Message`] のバリデーションをスキップするため、
-    /// データベースからすでにバリデーションされているデータを読み出すときなど、
-    /// データの信頼性が保証されている場合にのみ使用してください。
-    pub unsafe fn from_raw_parts(
-        id: MessageId,
-        related_answer: FormAnswer,
-        sender: User,
-        body: String,
-        timestamp: DateTime<Utc>,
-    ) -> Self {
-        Self {
-            id,
-            related_answer,
-            sender,
-            body,
-            timestamp,
-        }
-    }
-}
-
 #[cfg(test)]
 mod test {
     use test_case::test_case;
 
     use super::*;
+    use crate::form::question::models::QuestionType;
 
     #[test_case("TEXT"     => Ok(QuestionType::TEXT); "upper: TEXT")]
     #[test_case("text"     => Ok(QuestionType::TEXT); "lower: text")]
diff --git a/server/domain/src/form/question.rs b/server/domain/src/form/question.rs
new file mode 100644
index 00000000..e072fd8b
--- /dev/null
+++ b/server/domain/src/form/question.rs
@@ -0,0 +1 @@
+pub mod models;
diff --git a/server/domain/src/form/question/models.rs b/server/domain/src/form/question/models.rs
new file mode 100644
index 00000000..967d958d
--- /dev/null
+++ b/server/domain/src/form/question/models.rs
@@ -0,0 +1,89 @@
+#[cfg(test)]
+use common::test_utils::arbitrary_with_size;
+use derive_getters::Getters;
+use errors::domain::DomainError;
+#[cfg(test)]
+use proptest_derive::Arbitrary;
+use serde::{Deserialize, Serialize};
+use strum_macros::{Display, EnumString};
+
+use crate::form::models::FormId;
+
+pub type QuestionId = types::IntegerId<Question>;
+
+#[cfg_attr(test, derive(Arbitrary))]
+#[derive(Serialize, Deserialize, Clone, Getters, Debug, PartialEq)]
+pub struct Question {
+    #[serde(default)]
+    pub id: Option<QuestionId>,
+    pub form_id: FormId,
+    pub title: String,
+    pub description: Option<String>,
+    pub question_type: QuestionType,
+    #[cfg_attr(test, proptest(strategy = "arbitrary_with_size(1..100)"))]
+    #[serde(default)]
+    pub choices: Vec<String>,
+    pub is_required: bool,
+}
+
+impl Question {
+    pub fn new(
+        id: Option<QuestionId>,
+        form_id: FormId,
+        title: String,
+        description: Option<String>,
+        question_type: QuestionType,
+        choices: Vec<String>,
+        is_required: bool,
+    ) -> Self {
+        Self {
+            id,
+            form_id,
+            title,
+            description,
+            question_type,
+            choices,
+            is_required,
+        }
+    }
+
+    pub fn from_raw_parts(
+        id: Option<QuestionId>,
+        form_id: FormId,
+        title: String,
+        description: Option<String>,
+        question_type: QuestionType,
+        choices: Vec<String>,
+        is_required: bool,
+    ) -> Self {
+        Self {
+            id,
+            form_id,
+            title,
+            description,
+            question_type,
+            choices,
+            is_required,
+        }
+    }
+}
+
+#[cfg_attr(test, derive(Arbitrary))]
+#[derive(
+    Debug, Serialize, Deserialize, Clone, Copy, EnumString, PartialOrd, PartialEq, Display,
+)]
+#[strum(ascii_case_insensitive)]
+pub enum QuestionType {
+    TEXT,
+    SINGLE,
+    MULTIPLE,
+}
+
+impl TryFrom<String> for QuestionType {
+    type Error = DomainError;
+
+    fn try_from(value: String) -> Result<Self, Self::Error> {
+        use std::str::FromStr;
+        Self::from_str(&value).map_err(Into::into)
+    }
+}
diff --git a/server/domain/src/notification/models.rs b/server/domain/src/notification/models.rs
index 6f6d909c..3ec4aaa3 100644
--- a/server/domain/src/notification/models.rs
+++ b/server/domain/src/notification/models.rs
@@ -2,7 +2,7 @@ use derive_getters::Getters;
 use serde::Deserialize;
 
 use crate::{
-    form::models::MessageId, types::authorization_guard::AuthorizationGuardDefinitions,
+    form::message::models::MessageId, types::authorization_guard::AuthorizationGuardDefinitions,
     user::models::User,
 };
 
@@ -27,7 +27,7 @@ impl Notification {
     /// # Examples
     /// ```
     /// use domain::{
-    ///     form::models::MessageId,
+    ///     form::message::models::MessageId,
     ///     notification::models::{Notification, NotificationSource},
     ///     user::models::User,
     /// };
@@ -56,7 +56,7 @@ impl Notification {
     /// # Examples
     /// ```
     /// use domain::{
-    ///     form::models::MessageId,
+    ///     form::message::models::MessageId,
     ///     notification::models::{Notification, NotificationId, NotificationSource},
     ///     user::models::User,
     /// };
diff --git a/server/domain/src/repository/form_repository.rs b/server/domain/src/repository/form_repository.rs
index 611ba14a..bd43b3ec 100644
--- a/server/domain/src/repository/form_repository.rs
+++ b/server/domain/src/repository/form_repository.rs
@@ -3,10 +3,15 @@ use errors::Error;
 use mockall::automock;
 
 use crate::{
-    form::models::{
-        AnswerId, AnswerLabel, Comment, CommentId, DefaultAnswerTitle, Form, FormAnswer,
-        FormAnswerContent, FormDescription, FormId, FormTitle, Label, LabelId, Message, MessageId,
-        Question, ResponsePeriod, Visibility, WebhookUrl,
+    form::{
+        answer::models::{AnswerId, AnswerLabel, FormAnswer, FormAnswerContent},
+        comment::models::{Comment, CommentId},
+        message::models::{Message, MessageId},
+        models::{
+            DefaultAnswerTitle, Form, FormDescription, FormId, FormTitle, Label, LabelId,
+            ResponsePeriod, Visibility, WebhookUrl,
+        },
+        question::models::Question,
     },
     types::authorization_guard::{AuthorizationGuard, Create, Delete, Read, Update},
     user::models::User,
diff --git a/server/domain/src/repository/search_repository.rs b/server/domain/src/repository/search_repository.rs
index 04870315..db9b9382 100644
--- a/server/domain/src/repository/search_repository.rs
+++ b/server/domain/src/repository/search_repository.rs
@@ -3,7 +3,10 @@ use errors::Error;
 use mockall::automock;
 
 use crate::{
-    form::models::{Form, FormAnswerContent, Label},
+    form::{
+        answer::models::FormAnswerContent,
+        models::{Form, Label},
+    },
     search::models::Comment,
     user::models::User,
 };
diff --git a/server/domain/src/search/models.rs b/server/domain/src/search/models.rs
index b0a9df6d..553e9844 100644
--- a/server/domain/src/search/models.rs
+++ b/server/domain/src/search/models.rs
@@ -2,7 +2,11 @@ use serde::{Deserialize, Serialize};
 use uuid::Uuid;
 
 use crate::{
-    form::models::{AnswerId, CommentId, Form, FormAnswerContent, Label},
+    form::{
+        answer::models::{AnswerId, FormAnswerContent},
+        comment::models::CommentId,
+        models::{Form, Label},
+    },
     user::models::User,
 };
 
diff --git a/server/infra/outgoing/src/form_outgoing.rs b/server/infra/outgoing/src/form_outgoing.rs
index 9d8b388f..31666a4a 100644
--- a/server/infra/outgoing/src/form_outgoing.rs
+++ b/server/infra/outgoing/src/form_outgoing.rs
@@ -1,5 +1,10 @@
 use domain::{
-    form::models::{Comment, DefaultAnswerTitle, Form, FormAnswer, FormAnswerContent, Question},
+    form::{
+        answer::models::{FormAnswer, FormAnswerContent},
+        comment::models::Comment,
+        models::{DefaultAnswerTitle, Form},
+        question::models::Question,
+    },
     user::models::User,
 };
 use errors::infra::InfraError;
diff --git a/server/infra/resource/src/database/components.rs b/server/infra/resource/src/database/components.rs
index 60382a27..411df905 100644
--- a/server/infra/resource/src/database/components.rs
+++ b/server/infra/resource/src/database/components.rs
@@ -1,9 +1,14 @@
 use async_trait::async_trait;
 use domain::{
-    form::models::{
-        AnswerId, Comment, CommentId, DefaultAnswerTitle, Form, FormAnswer, FormAnswerContent,
-        FormDescription, FormId, FormTitle, Label, LabelId, Message, MessageId, Question,
-        ResponsePeriod, Visibility, WebhookUrl,
+    form::{
+        answer::models::{AnswerId, FormAnswer, FormAnswerContent},
+        comment::models::{Comment, CommentId},
+        message::models::{Message, MessageId},
+        models::{
+            DefaultAnswerTitle, Form, FormDescription, FormId, FormTitle, Label, LabelId,
+            ResponsePeriod, Visibility, WebhookUrl,
+        },
+        question::models::Question,
     },
     notification::models::{Notification, NotificationId},
     user::models::{Role, User},
diff --git a/server/infra/resource/src/database/form.rs b/server/infra/resource/src/database/form.rs
index 10a56e98..97d4a88c 100644
--- a/server/infra/resource/src/database/form.rs
+++ b/server/infra/resource/src/database/form.rs
@@ -3,10 +3,15 @@ use std::str::FromStr;
 use async_trait::async_trait;
 use chrono::{DateTime, Utc};
 use domain::{
-    form::models::{
-        AnswerId, Comment, CommentId, DefaultAnswerTitle, Form, FormAnswer, FormAnswerContent,
-        FormDescription, FormId, FormTitle, Label, LabelId, Message, MessageId, Question,
-        ResponsePeriod, Visibility, WebhookUrl,
+    form::{
+        answer::models::{AnswerId, FormAnswer, FormAnswerContent},
+        comment::models::{Comment, CommentId},
+        message::models::{Message, MessageId},
+        models::{
+            DefaultAnswerTitle, Form, FormDescription, FormId, FormTitle, Label, LabelId,
+            ResponsePeriod, Visibility, WebhookUrl,
+        },
+        question::models::Question,
     },
     user::models::{Role, User},
 };
@@ -642,7 +647,7 @@ impl FormDatabase for ConnectionPool {
                     .rev()
                     .zip((1..=last_insert_id).rev())
                     .filter(|(q, _)| {
-                        !q.choices.is_empty() && q.question_type != domain::form::models::QuestionType::TEXT
+                        !q.choices.is_empty() && q.question_type != domain::form::question::models::QuestionType::TEXT
                     })
                     .flat_map(|(question, question_id)| {
                         question
@@ -725,7 +730,7 @@ impl FormDatabase for ConnectionPool {
                 .rev()
                 .zip((1..=last_insert_id).rev())
                 .filter(|(q, _)| {
-                    !q.choices.is_empty() && q.question_type != domain::form::models::QuestionType::TEXT
+                    !q.choices.is_empty() && q.question_type != domain::form::question::models::QuestionType::TEXT
                 })
                 .flat_map(|(question, question_id)| {
                     question
diff --git a/server/infra/resource/src/database/search.rs b/server/infra/resource/src/database/search.rs
index f9f0204a..69531d0c 100644
--- a/server/infra/resource/src/database/search.rs
+++ b/server/infra/resource/src/database/search.rs
@@ -1,6 +1,9 @@
 use async_trait::async_trait;
 use domain::{
-    form::models::{Form, FormAnswerContent, Label},
+    form::{
+        answer::models::FormAnswerContent,
+        models::{Form, Label},
+    },
     search::models::Comment,
     user::models::User,
 };
diff --git a/server/infra/resource/src/dto.rs b/server/infra/resource/src/dto.rs
index 8eaacc5d..d7a6b0a2 100644
--- a/server/infra/resource/src/dto.rs
+++ b/server/infra/resource/src/dto.rs
@@ -2,9 +2,12 @@ use std::str::FromStr;
 
 use chrono::{DateTime, Utc};
 use domain::{
-    form::models::{
-        DefaultAnswerTitle, FormDescription, FormId, FormMeta, FormSettings, FormTitle, Question,
-        QuestionType, ResponsePeriod, WebhookUrl,
+    form::{
+        models::{
+            DefaultAnswerTitle, FormDescription, FormId, FormMeta, FormSettings, FormTitle,
+            ResponsePeriod, WebhookUrl,
+        },
+        question::models::{Question, QuestionType},
     },
     user::models::{Role, User},
 };
@@ -22,7 +25,7 @@ pub struct QuestionDto {
     pub is_required: bool,
 }
 
-impl TryFrom<QuestionDto> for domain::form::models::Question {
+impl TryFrom<QuestionDto> for domain::form::question::models::Question {
     type Error = errors::domain::DomainError;
 
     fn try_from(
@@ -100,7 +103,7 @@ pub struct FormAnswerContentDto {
     pub answer: String,
 }
 
-impl TryFrom<FormAnswerContentDto> for domain::form::models::FormAnswerContent {
+impl TryFrom<FormAnswerContentDto> for domain::form::answer::models::FormAnswerContent {
     type Error = errors::domain::DomainError;
 
     fn try_from(
@@ -110,7 +113,7 @@ impl TryFrom<FormAnswerContentDto> for domain::form::models::FormAnswerContent {
             answer,
         }: FormAnswerContentDto,
     ) -> Result<Self, Self::Error> {
-        Ok(domain::form::models::FormAnswerContent {
+        Ok(domain::form::answer::models::FormAnswerContent {
             answer_id: answer_id.into(),
             question_id: question_id.into(),
             answer,
@@ -140,7 +143,7 @@ pub struct CommentDto {
     pub commented_by: UserDto,
 }
 
-impl TryFrom<CommentDto> for domain::form::models::Comment {
+impl TryFrom<CommentDto> for domain::form::comment::models::Comment {
     type Error = errors::domain::DomainError;
 
     fn try_from(
@@ -152,7 +155,7 @@ impl TryFrom<CommentDto> for domain::form::models::Comment {
             commented_by,
         }: CommentDto,
     ) -> Result<Self, Self::Error> {
-        Ok(domain::form::models::Comment {
+        Ok(domain::form::comment::models::Comment {
             answer_id: answer_id.into(),
             comment_id: comment_id.into(),
             content,
@@ -172,7 +175,7 @@ pub struct FormAnswerDto {
     pub title: Option<String>,
 }
 
-impl TryFrom<FormAnswerDto> for domain::form::models::FormAnswer {
+impl TryFrom<FormAnswerDto> for domain::form::answer::models::FormAnswer {
     type Error = errors::domain::DomainError;
 
     fn try_from(
@@ -186,7 +189,7 @@ impl TryFrom<FormAnswerDto> for domain::form::models::FormAnswer {
             title,
         }: FormAnswerDto,
     ) -> Result<Self, Self::Error> {
-        Ok(domain::form::models::FormAnswer {
+        Ok(domain::form::answer::models::FormAnswer {
             id: id.into(),
             user: User {
                 name: user_name,
@@ -206,7 +209,7 @@ pub struct AnswerLabelDto {
     pub name: String,
 }
 
-impl TryFrom<AnswerLabelDto> for domain::form::models::AnswerLabel {
+impl TryFrom<AnswerLabelDto> for domain::form::answer::models::AnswerLabel {
     type Error = errors::domain::DomainError;
 
     fn try_from(
@@ -216,7 +219,7 @@ impl TryFrom<AnswerLabelDto> for domain::form::models::AnswerLabel {
             name,
         }: AnswerLabelDto,
     ) -> Result<Self, Self::Error> {
-        Ok(domain::form::models::AnswerLabel {
+        Ok(domain::form::answer::models::AnswerLabel {
             id: id.into(),
             answer_id: answer_id.into(),
             name,
@@ -248,7 +251,7 @@ pub struct MessageDto {
     pub timestamp: DateTime<Utc>,
 }
 
-impl TryFrom<MessageDto> for domain::form::models::Message {
+impl TryFrom<MessageDto> for domain::form::message::models::Message {
     type Error = errors::domain::DomainError;
 
     fn try_from(
@@ -261,7 +264,7 @@ impl TryFrom<MessageDto> for domain::form::models::Message {
         }: MessageDto,
     ) -> Result<Self, Self::Error> {
         unsafe {
-            Ok(domain::form::models::Message::from_raw_parts(
+            Ok(domain::form::message::models::Message::from_raw_parts(
                 id.into(),
                 related_answer.try_into()?,
                 sender.try_into()?,
diff --git a/server/infra/resource/src/repository/form_repository_impl.rs b/server/infra/resource/src/repository/form_repository_impl.rs
index b211cfa9..9411846b 100644
--- a/server/infra/resource/src/repository/form_repository_impl.rs
+++ b/server/infra/resource/src/repository/form_repository_impl.rs
@@ -1,9 +1,14 @@
 use async_trait::async_trait;
 use domain::{
-    form::models::{
-        AnswerId, AnswerLabel, Comment, CommentId, DefaultAnswerTitle, Form, FormAnswer,
-        FormAnswerContent, FormDescription, FormId, FormTitle, Label, LabelId, Message, MessageId,
-        Question, ResponsePeriod, Visibility, WebhookUrl,
+    form::{
+        answer::models::{AnswerId, AnswerLabel, FormAnswer, FormAnswerContent},
+        comment::models::{Comment, CommentId},
+        message::models::{Message, MessageId},
+        models::{
+            DefaultAnswerTitle, Form, FormDescription, FormId, FormTitle, Label, LabelId,
+            ResponsePeriod, Visibility, WebhookUrl,
+        },
+        question::models::Question,
     },
     repository::form_repository::FormRepository,
     types::authorization_guard::{AuthorizationGuard, Create, Delete, Read, Update},
diff --git a/server/infra/resource/src/repository/search_repository_impl.rs b/server/infra/resource/src/repository/search_repository_impl.rs
index 0bec2bf8..e2cf7c2e 100644
--- a/server/infra/resource/src/repository/search_repository_impl.rs
+++ b/server/infra/resource/src/repository/search_repository_impl.rs
@@ -1,6 +1,9 @@
 use async_trait::async_trait;
 use domain::{
-    form::models::{Form, FormAnswerContent, Label},
+    form::{
+        answer::models::FormAnswerContent,
+        models::{Form, Label},
+    },
     repository::search_repository::SearchRepository,
     search::models::Comment,
     user::models::User,
diff --git a/server/presentation/src/form_handler.rs b/server/presentation/src/form_handler.rs
index 3a9231f8..45cade35 100644
--- a/server/presentation/src/form_handler.rs
+++ b/server/presentation/src/form_handler.rs
@@ -5,8 +5,11 @@ use axum::{
     Extension, Json,
 };
 use domain::{
-    form::models::{
-        AnswerId, Comment, CommentId, FormId, Label, LabelId, MessageId, Visibility::PRIVATE,
+    form::{
+        answer::models::AnswerId,
+        comment::models::{Comment, CommentId},
+        message::models::MessageId,
+        models::{FormId, Label, LabelId, Visibility::PRIVATE},
     },
     repository::Repositories,
     user::models::{Role::StandardUser, User},
diff --git a/server/presentation/src/schemas/form/form_request_schemas.rs b/server/presentation/src/schemas/form/form_request_schemas.rs
index 5de80caf..e3659301 100644
--- a/server/presentation/src/schemas/form/form_request_schemas.rs
+++ b/server/presentation/src/schemas/form/form_request_schemas.rs
@@ -1,82 +1,86 @@
-use domain::form::models::{
-    AnswerId, DefaultAnswerTitle, FormAnswerContent, FormDescription, FormId, FormTitle, LabelId,
-    Question, ResponsePeriod, Visibility, WebhookUrl,
-};
-use serde::Deserialize;
-
-#[derive(Deserialize, Debug)]
-pub struct OffsetAndLimit {
-    pub offset: Option<u32>,
-    pub limit: Option<u32>,
-}
-
-#[derive(Deserialize, Debug)]
-pub struct FormCreateSchema {
-    pub title: FormTitle,
-    pub description: FormDescription,
-}
-
-#[derive(Deserialize, Debug)]
-pub struct FormUpdateSchema {
-    #[serde(default)]
-    pub title: Option<FormTitle>,
-    #[serde(default)]
-    pub description: Option<FormDescription>,
-    #[serde(default)]
-    pub has_response_period: Option<bool>,
-    #[serde(default)]
-    pub response_period: Option<ResponsePeriod>,
-    #[serde(default)]
-    pub webhook: Option<WebhookUrl>,
-    #[serde(default)]
-    pub default_answer_title: Option<DefaultAnswerTitle>,
-    #[serde(default)]
-    pub visibility: Option<Visibility>,
-    #[serde(default)]
-    pub answer_visibility: Option<Visibility>,
-}
-
-#[derive(Deserialize, Debug)]
-pub struct AnswersPostSchema {
-    pub form_id: FormId,
-    pub title: DefaultAnswerTitle,
-    pub answers: Vec<FormAnswerContent>,
-}
-
-#[derive(Deserialize, Debug)]
-pub struct AnswerUpdateSchema {
-    #[serde(default)]
-    pub title: Option<String>,
-}
-
-#[derive(Deserialize, Debug)]
-pub struct FormQuestionUpdateSchema {
-    pub form_id: FormId,
-    pub questions: Vec<Question>,
-}
-
-#[derive(Deserialize, Debug)]
-pub struct CommentPostSchema {
-    pub answer_id: AnswerId,
-    pub content: String,
-}
-
-#[derive(Deserialize, Debug)]
-pub struct LabelSchema {
-    pub name: String,
-}
-
-#[derive(Deserialize, Debug)]
-pub struct ReplaceAnswerLabelSchema {
-    pub labels: Vec<LabelId>,
-}
-
-#[derive(Deserialize, Debug)]
-pub struct PostedMessageSchema {
-    pub body: String,
-}
-
-#[derive(Deserialize, Debug)]
-pub struct MessageUpdateSchema {
-    pub body: String,
-}
+use domain::form::{
+    answer::models::{AnswerId, FormAnswerContent},
+    models::{
+        DefaultAnswerTitle, FormDescription, FormId, FormTitle, LabelId, ResponsePeriod,
+        Visibility, WebhookUrl,
+    },
+    question::models::Question,
+};
+use serde::Deserialize;
+
+#[derive(Deserialize, Debug)]
+pub struct OffsetAndLimit {
+    pub offset: Option<u32>,
+    pub limit: Option<u32>,
+}
+
+#[derive(Deserialize, Debug)]
+pub struct FormCreateSchema {
+    pub title: FormTitle,
+    pub description: FormDescription,
+}
+
+#[derive(Deserialize, Debug)]
+pub struct FormUpdateSchema {
+    #[serde(default)]
+    pub title: Option<FormTitle>,
+    #[serde(default)]
+    pub description: Option<FormDescription>,
+    #[serde(default)]
+    pub has_response_period: Option<bool>,
+    #[serde(default)]
+    pub response_period: Option<ResponsePeriod>,
+    #[serde(default)]
+    pub webhook: Option<WebhookUrl>,
+    #[serde(default)]
+    pub default_answer_title: Option<DefaultAnswerTitle>,
+    #[serde(default)]
+    pub visibility: Option<Visibility>,
+    #[serde(default)]
+    pub answer_visibility: Option<Visibility>,
+}
+
+#[derive(Deserialize, Debug)]
+pub struct AnswersPostSchema {
+    pub form_id: FormId,
+    pub title: DefaultAnswerTitle,
+    pub answers: Vec<FormAnswerContent>,
+}
+
+#[derive(Deserialize, Debug)]
+pub struct AnswerUpdateSchema {
+    #[serde(default)]
+    pub title: Option<String>,
+}
+
+#[derive(Deserialize, Debug)]
+pub struct FormQuestionUpdateSchema {
+    pub form_id: FormId,
+    pub questions: Vec<Question>,
+}
+
+#[derive(Deserialize, Debug)]
+pub struct CommentPostSchema {
+    pub answer_id: AnswerId,
+    pub content: String,
+}
+
+#[derive(Deserialize, Debug)]
+pub struct LabelSchema {
+    pub name: String,
+}
+
+#[derive(Deserialize, Debug)]
+pub struct ReplaceAnswerLabelSchema {
+    pub labels: Vec<LabelId>,
+}
+
+#[derive(Deserialize, Debug)]
+pub struct PostedMessageSchema {
+    pub body: String,
+}
+
+#[derive(Deserialize, Debug)]
+pub struct MessageUpdateSchema {
+    pub body: String,
+}
diff --git a/server/presentation/src/schemas/form/form_response_schemas.rs b/server/presentation/src/schemas/form/form_response_schemas.rs
index 61766137..c75e9ffe 100644
--- a/server/presentation/src/schemas/form/form_response_schemas.rs
+++ b/server/presentation/src/schemas/form/form_response_schemas.rs
@@ -91,8 +91,8 @@ pub(crate) struct AnswerContent {
     answer: String,
 }
 
-impl From<domain::form::models::FormAnswerContent> for AnswerContent {
-    fn from(val: domain::form::models::FormAnswerContent) -> Self {
+impl From<domain::form::answer::models::FormAnswerContent> for AnswerContent {
+    fn from(val: domain::form::answer::models::FormAnswerContent) -> Self {
         AnswerContent {
             question_id: val.question_id.into(),
             answer: val.answer,
@@ -107,8 +107,8 @@ pub(crate) struct AnswerComment {
     commented_by: User,
 }
 
-impl From<domain::form::models::Comment> for AnswerComment {
-    fn from(val: domain::form::models::Comment) -> Self {
+impl From<domain::form::comment::models::Comment> for AnswerComment {
+    fn from(val: domain::form::comment::models::Comment) -> Self {
         AnswerComment {
             content: val.content,
             timestamp: val.timestamp,
@@ -123,8 +123,8 @@ pub(crate) struct AnswerLabels {
     name: String,
 }
 
-impl From<domain::form::models::AnswerLabel> for AnswerLabels {
-    fn from(val: domain::form::models::AnswerLabel) -> Self {
+impl From<domain::form::answer::models::AnswerLabel> for AnswerLabels {
+    fn from(val: domain::form::answer::models::AnswerLabel) -> Self {
         AnswerLabels {
             id: val.id.into(),
             name: val.name,
@@ -146,10 +146,10 @@ pub(crate) struct FormAnswer {
 
 impl FormAnswer {
     pub fn new(
-        answer: domain::form::models::FormAnswer,
-        answer_contents: Vec<domain::form::models::FormAnswerContent>,
-        comments: Vec<domain::form::models::Comment>,
-        labels: Vec<domain::form::models::AnswerLabel>,
+        answer: domain::form::answer::models::FormAnswer,
+        answer_contents: Vec<domain::form::answer::models::FormAnswerContent>,
+        comments: Vec<domain::form::comment::models::Comment>,
+        labels: Vec<domain::form::answer::models::AnswerLabel>,
     ) -> Self {
         FormAnswer {
             id: answer.id.into(),
diff --git a/server/usecase/src/dto.rs b/server/usecase/src/dto.rs
index a41e6d46..60ccf789 100644
--- a/server/usecase/src/dto.rs
+++ b/server/usecase/src/dto.rs
@@ -1,8 +1,11 @@
-use domain::form::models::{AnswerLabel, Comment, FormAnswer, FormAnswerContent};
-
-pub struct AnswerDto {
-    pub form_answer: FormAnswer,
-    pub contents: Vec<FormAnswerContent>,
-    pub labels: Vec<AnswerLabel>,
-    pub comments: Vec<Comment>,
-}
+use domain::form::{
+    answer::models::{AnswerLabel, FormAnswer, FormAnswerContent},
+    comment::models::Comment,
+};
+
+pub struct AnswerDto {
+    pub form_answer: FormAnswer,
+    pub contents: Vec<FormAnswerContent>,
+    pub labels: Vec<AnswerLabel>,
+    pub comments: Vec<Comment>,
+}
diff --git a/server/usecase/src/form.rs b/server/usecase/src/form.rs
index 6f7394e2..593c8720 100644
--- a/server/usecase/src/form.rs
+++ b/server/usecase/src/form.rs
@@ -1,9 +1,14 @@
 use chrono::Utc;
 use domain::{
-    form::models::{
-        AnswerId, Comment, CommentId, DefaultAnswerTitle, Form, FormAnswerContent, FormDescription,
-        FormId, FormTitle, Label, LabelId, Message, MessageId, Question, ResponsePeriod,
-        Visibility, Visibility::PUBLIC, WebhookUrl,
+    form::{
+        answer::models::{AnswerId, FormAnswerContent},
+        comment::models::{Comment, CommentId},
+        message::models::{Message, MessageId},
+        models::{
+            DefaultAnswerTitle, Form, FormDescription, FormId, FormTitle, Label, LabelId,
+            ResponsePeriod, Visibility, Visibility::PUBLIC, WebhookUrl,
+        },
+        question::models::Question,
     },
     notification::models::{Notification, NotificationSource},
     repository::{