diff --git a/.github/workflows/codeql-analysis.yml b/.github/workflows/codeql-analysis.yml
index 18b583ac..348f3296 100644
--- a/.github/workflows/codeql-analysis.yml
+++ b/.github/workflows/codeql-analysis.yml
@@ -3,7 +3,7 @@ name: "Code Scanning"
 on:
   push:
     branches:
-      - master
+      - main
   pull_request:
 
 jobs:
diff --git a/.github/workflows/dev-image.yml b/.github/workflows/dev-image.yml
index 2a27412f..99a9cd85 100644
--- a/.github/workflows/dev-image.yml
+++ b/.github/workflows/dev-image.yml
@@ -3,7 +3,7 @@ name: 'Dev Image CI'
 on:
   push:
     branches:
-      - master
+      - main
     paths:
       - '.github/workflows/dev-image.yml'
       - '.dockerignore'
diff --git a/.github/workflows/label-commenter.yml b/.github/workflows/label-commenter.yml
index 3dfedad8..b1363ec3 100644
--- a/.github/workflows/label-commenter.yml
+++ b/.github/workflows/label-commenter.yml
@@ -16,7 +16,7 @@ jobs:
     steps:
       - uses: actions/checkout@v2
         with:
-          ref: master
+          ref: main
 
       - name: Label Commenter
         uses: peaceiris/actions-label-commenter@v1.3.7
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 2a038126..37d42d30 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -3,7 +3,7 @@ name: 'Test'
 on:
   push:
     branches:
-      - master
+      - main
     paths-ignore:
       - '**.md'
   pull_request:
diff --git a/README.md b/README.md
index eb45e65f..4376e024 100644
--- a/README.md
+++ b/README.md
@@ -1,11 +1,11 @@
-[![license](https://img.shields.io/github/license/peaceiris/actions-hugo.svg)](https://github.com/peaceiris/actions-hugo/blob/master/LICENSE)
+[![license](https://img.shields.io/github/license/peaceiris/actions-hugo.svg)](https://github.com/peaceiris/actions-hugo/blob/main/LICENSE)
 [![release](https://img.shields.io/github/release/peaceiris/actions-hugo.svg)](https://github.com/peaceiris/actions-hugo/releases/latest)
 [![GitHub release date](https://img.shields.io/github/release-date/peaceiris/actions-hugo.svg)](https://github.com/peaceiris/actions-hugo/releases)
 [![Release Feed](https://img.shields.io/badge/release-feed-yellow)](https://github.com/peaceiris/actions-hugo/releases.atom)
-![Test](https://github.com/peaceiris/actions-hugo/workflows/Test/badge.svg?branch=master&event=push)
+![Test](https://github.com/peaceiris/actions-hugo/workflows/Test/badge.svg?branch=main&event=push)
 
 [![CodeFactor](https://www.codefactor.io/repository/github/peaceiris/actions-hugo/badge)](https://www.codefactor.io/repository/github/peaceiris/actions-hugo)
-[![codecov](https://codecov.io/gh/peaceiris/actions-hugo/branch/master/graph/badge.svg)](https://codecov.io/gh/peaceiris/actions-hugo)
+[![codecov](https://codecov.io/gh/peaceiris/actions-hugo/branch/main/graph/badge.svg)](https://codecov.io/gh/peaceiris/actions-hugo)
 [![Maintainability](https://api.codeclimate.com/v1/badges/ebf2eef3a046b396ba9c/maintainability)](https://codeclimate.com/github/peaceiris/actions-hugo/maintainability)
 
 <img width="400" alt="GitHub Actions for Hugo" src="./images/ogp.svg">
@@ -75,7 +75,7 @@ name: github pages
 on:
   push:
     branches:
-      - master
+      - main
 
 jobs:
   deploy:
@@ -210,7 +210,7 @@ name: github pages
 on:
   push:
     branches:
-      - master
+      - main
 
 jobs:
   deploy:
@@ -259,7 +259,7 @@ name: github pages
 on:
   push:
     branches:
-      - master
+      - main
 
 jobs:
   deploy:
@@ -310,7 +310,7 @@ jobs:
 
 - [MIT License - peaceiris/actions-hugo]
 
-[MIT License - peaceiris/actions-hugo]: https://github.com/peaceiris/actions-hugo/blob/master/LICENSE
+[MIT License - peaceiris/actions-hugo]: https://github.com/peaceiris/actions-hugo/blob/main/LICENSE
 
 
 
diff --git a/release.sh b/release.sh
index f63a1473..eb9efe05 100755
--- a/release.sh
+++ b/release.sh
@@ -3,8 +3,10 @@
 # fail on unset variables and command errors
 set -eu -o pipefail # -x: is for debugging
 
-if [ "$(git branch --show-current)" != "master" ]; then
-  echo "$0: Current branch is not master" 1>&2
+DEFAULT_BRANCH="main"
+
+if [ "$(git branch --show-current)" != "${DEFAULT_BRANCH}" ]; then
+  echo "$0: Current branch is not ${DEFAULT_BRANCH}" 1>&2
   exit 1
 fi
 
@@ -26,7 +28,7 @@ if [ "${res}" = "n" ]; then
 fi
 
 git fetch origin
-git pull origin master
+git pull origin "${DEFAULT_BRANCH}"
 git tag -d v2 || true
 git pull origin --tags
 
@@ -44,5 +46,5 @@ rm -rf ./lib
 git commit -m "chore(release): Remove build assets [skip ci]"
 
 TAG_NAME="v$(jq -r '.version' ./package.json)"
-git push origin master
+git push origin "${DEFAULT_BRANCH}"
 git push origin "${TAG_NAME}"