diff --git a/.github/workflows/auto-assign.yml b/.github/workflows/auto-assign.yml
index 0f160b8..01008f5 100644
--- a/.github/workflows/auto-assign.yml
+++ b/.github/workflows/auto-assign.yml
@@ -10,22 +10,31 @@ on:
       - opened
       - reopened
 
-permissions:
-  issues: write
-  pull-requests: write
-
 env:
-  REPOSITORY_OWNER: OpenUp-LabTakizawa
+  GH_TOKEN: ${{ github.token }}
+  MEMBERS: |
+    HaradaTakayuki
+    kazutan1230
+    Marukome0743
+    tanePON
 
 jobs:
-  run:
+  assign:
     runs-on: ubuntu-latest
 
     steps:
-    - name: Auto-assign issue
-      if: github.repository_owner == env.REPOSITORY_OWNER
-      uses: pozil/auto-assign-issue@v1
-      with:
-          assignees: HaradaTakayuki,kazutan1230,Marukome0743,tanePON
-          numOfAssignee: 1
-          abortIfPreviousAssignees: true
+      - name: Assign Issue
+        if: github.event_name == 'issues' && toJSON(github.event.issue.assignees) == '[]'
+        run: |
+          echo "$MEMBERS" |
+            tail -n +2 |
+            shuf -n 1 |
+            xargs gh issue edit ${{ github.event.issue.number }} --repo ${{ github.repository }} --add-assignee
+
+      - name: Assign Pull Request
+        if: github.event_name == 'pull_request_target' && toJSON(github.event.pull_request.assignees) == '[]'
+        run: |
+          echo "$MEMBERS" |
+            tail -n +2 |
+            shuf -n 1 |
+            xargs gh pr edit ${{ github.event.pull_request.number }} --repo ${{ github.repository }} --add-assignee