diff --git a/.github/dependabot.yml b/.github/dependabot.yml
new file mode 100644
index 0000000..f0ec6c0
--- /dev/null
+++ b/.github/dependabot.yml
@@ -0,0 +1,11 @@
+# https://docs.github.com/code-security/dependabot/working-with-dependabot/dependabot-options-reference
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "monthly"
+      time: "19:00"
+      timezone: "Asia/Tokyo"
+    cooldown:
+      default-days: 7
diff --git a/.github/workflows/add_assignee_to_pr.yml b/.github/workflows/add_assignee_to_pr.yml
new file mode 100644
index 0000000..0e24d36
--- /dev/null
+++ b/.github/workflows/add_assignee_to_pr.yml
@@ -0,0 +1,11 @@
+name: Add assignee to PR
+
+on:
+  pull_request:
+    types: [opened]
+
+jobs:
+  add-assignee-to-pr:
+    uses: masutaka/actions/.github/workflows/add_assignee_to_pr.yml@main
+    permissions:
+      pull-requests: write