diff --git a/seichi-onp-k8s/manifests/seichi-kubernetes/apps/cluster-wide-apps/app-of-other-apps/argo-workflows.yaml b/seichi-onp-k8s/manifests/seichi-kubernetes/apps/cluster-wide-apps/app-of-other-apps/argo-workflows.yaml
index 2020a5b8c..bbd71cb84 100644
--- a/seichi-onp-k8s/manifests/seichi-kubernetes/apps/cluster-wide-apps/app-of-other-apps/argo-workflows.yaml
+++ b/seichi-onp-k8s/manifests/seichi-kubernetes/apps/cluster-wide-apps/app-of-other-apps/argo-workflows.yaml
@@ -1,3 +1,17 @@
+apiVersion: v1
+kind: Service
+metadata:
+  name: argo-workflows-webhook-service
+  namespace: argocd
+spec:
+  selector:
+    app: argo-workflows
+  ports:
+    - name: argo-workflows-webhook
+      protocol: TCP
+      port: 12000
+      targetPort: 12000
+---
 apiVersion: argoproj.io/v1alpha1
 kind: Application
 metadata: