diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
index 807c92d..9516dc6 100644
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -18,7 +18,7 @@ jobs:
   publish:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - uses: actions/setup-python@v5
         with:
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 41bb516..2acb1db 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -15,7 +15,7 @@ jobs:
     if: github.event.action != 'labeled'
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       # Bump version on merging Pull Requests with specific labels.
       # (bump:major,bump:minor,bump:patch)
@@ -54,6 +54,6 @@ jobs:
     if: github.event.action == 'labeled'
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Post bumpr status comment
         uses: haya14busa/action-bumpr@v1
diff --git a/.github/workflows/reviewdog.yml b/.github/workflows/reviewdog.yml
index 10a1401..ff8ffdd 100644
--- a/.github/workflows/reviewdog.yml
+++ b/.github/workflows/reviewdog.yml
@@ -9,7 +9,7 @@ jobs:
     name: runner / shellcheck
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: haya14busa/action-cond@v1
         id: reporter
         with:
@@ -26,7 +26,7 @@ jobs:
     name: runner / misspell
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: reviewdog/action-misspell@v1
         with:
           github_token: ${{ secrets.github_token }}
@@ -38,7 +38,7 @@ jobs:
     name: runner /  alex
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: reviewdog/action-alex@v1
         with:
           github_token: ${{ secrets.github_token }}
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 1b9ef43..98aa230 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -13,12 +13,12 @@ jobs:
         python-version: ['3.10']
     steps:
       # Checkout this repo and template project for validation testing.
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with: 
           repository: altcoder/template-python
           path: pyproject
           clean: true
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           path: pyaction
           clean: true
diff --git a/.github/workflows/validation.yml b/.github/workflows/validation.yml
index 3302511..605700b 100644
--- a/.github/workflows/validation.yml
+++ b/.github/workflows/validation.yml
@@ -24,7 +24,7 @@ jobs:
           - tools: pytest
             args: -m integration
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: ${{ matrix.tools }}
         uses: altcoder/action-python@v0.1
         with: