diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index a3404a82be..58012035b4 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -101,7 +101,7 @@ jobs:
       uses: cypress-io/github-action@v2
       with:
         install: false
-        start: npm run start:test
+        start: yarn start:test
         wait-on: 'http://localhost:61812'
         headless: false
         browser: ${{ matrix.browser }}
diff --git a/CHANGELOG.md b/CHANGELOG.md
index bc7b41780d..d372ecf7d2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -187,7 +187,7 @@ You should also include the user name that made the change.
 ## 12.104.0 (2022/02/09)
 
 ### Note
-ビルドする前に`npm run clean`を実行してください。
+ビルドする前に`yarn clean`を実行してください。
 
 このリリースはマイグレーションの規模が大きいため、インスタンスによってはマイグレーションに時間がかかる可能性があります。
 マイグレーションが終わらない場合は、チャートの情報はリセットされてしまいますが`__chart__`で始まるテーブルの**レコード**を全て削除(テーブル自体は消さないでください)してから再度試す方法もあります。
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 135a3e140c..67ffbfe401 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -44,7 +44,7 @@ Thank you for your PR! Before creating a PR, please check the following:
 - Check if there are any documents that need to be created or updated due to this change.
 - If you have added a feature or fixed a bug, please add a test case if possible.
 - Please make sure that tests and Lint are passed in advance.
-  - You can run it with `npm run test` and `npm run lint`. [See more info](#testing)
+  - You can run it with `yarn test` and `yarn lint`. [See more info](#testing)
 - If this PR includes UI changes, please attach a screenshot in the text.
 
 Thanks for your cooperation 🤗
@@ -92,7 +92,7 @@ If your language is not listed in Crowdin, please open an issue.
 ![Crowdin](https://d322cqt584bo4o.cloudfront.net/misskey/localized.svg)
 
 ## Development
-During development, it is useful to use the `npm run dev` command.
+During development, it is useful to use the `yarn dev` command.
 This command monitors the server-side and client-side source files and automatically builds them if they are modified.
 In addition, it will also automatically start the Misskey server process.
 
@@ -112,7 +112,7 @@ Alternatively, prepare an empty (data can be erased) DB and edit `.config/test.y
 
 Run all test.
 ```
-npm run test
+yarn test
 ```
 
 #### Run specify test
diff --git a/package.json b/package.json
index 83211f4fbb..122bf79e80 100644
--- a/package.json
+++ b/package.json
@@ -17,22 +17,22 @@
 		"build": "yarn workspaces foreach run build",
 		"start": "cd packages/backend && yarn node --experimental-json-modules ./built/index.js",
 		"start:test": "cd packages/backend && cross-env NODE_ENV=test yarn node --experimental-json-modules ./built/index.js",
-		"init": "npm run migrate",
+		"init": "yarn migrate",
 		"migrate": "cd packages/backend && npx typeorm migration:run -d ormconfig.js",
-		"migrateandstart": "npm run migrate && npm run start",
+		"migrateandstart": "yarn migrate && yarn start",
 		"gulp": "gulp build",
-		"watch": "npm run dev",
+		"watch": "yarn dev",
 		"dev": "node ./scripts/dev.js",
 		"lint": "yarn workspaces foreach run lint",
 		"cy:open": "cypress open",
 		"cy:run": "cypress run",
 		"e2e": "start-server-and-test start:test http://localhost:61812 cy:run",
 		"mocha": "cd packages/backend && cross-env NODE_ENV=test TS_NODE_FILES=true TS_NODE_TRANSPILE_ONLY=true TS_NODE_PROJECT=\"./test/tsconfig.json\" npx mocha",
-		"test": "npm run mocha",
+		"test": "yarn mocha",
 		"format": "gulp format",
 		"clean": "node ./scripts/clean.js",
 		"clean-all": "node ./scripts/clean-all.js",
-		"cleanall": "npm run clean-all"
+		"cleanall": "yarn clean-all"
 	},
 	"dependencies": {
 		"eslint": "^8.16.0",
diff --git a/packages/backend/package.json b/packages/backend/package.json
index f70e64883b..0cca8e4463 100644
--- a/packages/backend/package.json
+++ b/packages/backend/package.json
@@ -8,7 +8,7 @@
 		"watch": "node watch.mjs",
 		"lint": "eslint --quiet \"src/**/*.ts\"",
 		"mocha": "cross-env NODE_ENV=test TS_NODE_FILES=true TS_NODE_TRANSPILE_ONLY=true TS_NODE_PROJECT=\"./test/tsconfig.json\" mocha",
-		"test": "npm run mocha"
+		"test": "yarn mocha"
 	},
 	"packageManager": "yarn@3.2.1",
 	"resolutions": {