diff --git a/README.md b/README.md
index 86bdb2f..3facb17 100644
--- a/README.md
+++ b/README.md
@@ -3,22 +3,21 @@
 [![PkgGoDev](https://pkg.go.dev/badge/github.com/cybozu-go/golang-custom-analyzer?tab=overview)](https://pkg.go.dev/github.com/cybozu-go/golang-custom-analyzer?tab=overview)
 [![Go Report Card](https://goreportcard.com/badge/github.com/cybozu-go/golang-custom-analyzer)](https://goreportcard.com/report/github.com/cybozu-go/golang-custom-analyzer)
 
-golang custom analyzer
-======================
+# golang custom analyzer
 
-This repository contains custom analysers for Go.
+This repository contains custom analyzers for Go.
 
 ## custom-checker
 
-`custom-checker` is the program to run the following analysers at once:
+`custom-checker` is the program to run the following analyzers at once:
 
 - `eventuallycheck`
 - `restrictpkg`
 
 ### Usage
 
-```console
-$ custom-checker -restrictpkg.packages=html/template,log targetfile.go
+```sh
+custom-checker -restrictpkg.packages=html/template,log targetfile.go
 ```
 
 ## `eventuallycheck`
@@ -27,8 +26,8 @@ $ custom-checker -restrictpkg.packages=html/template,log targetfile.go
 
 ### Usage
 
-```console
-$ eventuallycheck [FILES]
+```sh
+eventuallycheck [FILES]
 ```
 
 ### Target functions
@@ -46,6 +45,6 @@ $ eventuallycheck [FILES]
 
 Let `PACKAGE1` and `PACKAGE2` be the names of the packages you want to restrict.
 
-```console
-$ restrictpkg -packages PACKAGE1,PACKAGE2,...
+```sh
+restrictpkg -packages PACKAGE1,PACKAGE2,...
 ```
diff --git a/docs/release.md b/docs/release.md
new file mode 100644
index 0000000..cff9ee2
--- /dev/null
+++ b/docs/release.md
@@ -0,0 +1,34 @@
+# Release procedure
+
+This document describes how to release a new version.
+
+## Labeling
+
+Release notes are automatically generated based on PRs included in the release.
+Those PRs are categorized based on the label assigned to them.
+Please refer to `.github/release.yml` for the kind of labels.
+
+## Versioning
+
+Follow [semantic versioning 2.0.0][semver] to choose the new version number.
+
+## Bump version
+
+1. Determine a new version number. Then set `VERSION` variable.
+
+    ```sh
+    # Set VERSION and confirm it. It should not have "v" prefix.
+    VERSION=x.y.z
+    echo $VERSION
+    ```
+
+2. Add a git tag to the main HEAD, then push it.
+
+    ```sh
+    git checkout main
+    git tag -a -m "Release v$VERSION" "v$VERSION"
+    git tag -ln | grep $VERSION
+    git push origin v$VERSION
+    ```
+
+[semver]: https://semver.org/spec/v2.0.0.html