diff --git a/Dockerfile b/Dockerfile
index 550abda..c236269 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -31,11 +31,12 @@ RUN echo "deb https://repo.scala-sbt.org/scalasbt/debian all main" | tee /etc/ap
 RUN apt-get update && \
     apt-get install -y sbt
 
-# localeの設定
-RUN locale-gen en_US.UTF-8  
-ENV LANG en_US.UTF-8  
-ENV LANGUAGE en_US:en  
-ENV LC_ALL en_US.UTF-8
+# 日本語関連のパーケージをインストール
+RUN apt-get install -y language-pack-ja-base language-pack-ja
+
+# ロケールを日本語に設定する
+RUN update-locale LANG=ja_JP.UTF-8 LANGUAGE="ja_JP:ja" && \
+    echo "export LANG=ja_JP.UTF-8" >> /home/$USERNAME/.bashrc
 
 COPY --from=build-env --link /app/target/release/seichiassist-downloader /
 CMD ["./seichiassist-downloader"]