diff --git a/.gitea/workflows/update-images.yaml b/.gitea/workflows/update-images.yaml
index c73667f..4e03e94 100644
--- a/.gitea/workflows/update-images.yaml
+++ b/.gitea/workflows/update-images.yaml
@@ -140,19 +140,51 @@ jobs:
       - name: Update Helm Repository Index
         if: steps.check_update.outputs.update_needed == 'true'
         run: |
+          set -e
           WP_VERSION="${{ steps.wordpress.outputs.wp_version }}"
           CHART_NAME=$(grep '^name:' Chart.yaml | awk '{print $2}')
           PACKAGE_FILE="${CHART_NAME}-${WP_VERSION}.tgz"
-          git fetch origin gh-pages || git checkout --orphan gh-pages
-          git checkout gh-pages || (git checkout --orphan gh-pages && git rm -rf .)
-          mv "${PACKAGE_FILE}" .
-          helm repo index . --url https://gitea.example.com/${GITHUB_REPOSITORY}/raw/branch/gh-pages
+          
+          echo "Preparing Helm repository update..."
+          
+          # パッケージファイルを一時ディレクトリに移動
+          mkdir -p /tmp/helm-repo
+          cp "${PACKAGE_FILE}" /tmp/helm-repo/
+          
+          # gh-pagesブランチの処理
+          if git ls-remote --heads origin gh-pages | grep gh-pages; then
+            echo "gh-pages branch exists, checking out..."
+            git fetch origin gh-pages
+            git checkout gh-pages
+          else
+            echo "Creating new gh-pages branch..."
+            git checkout --orphan gh-pages
+            git rm -rf . || true
+            echo "# Helm Repository" > README.md
+            git add README.md
+            git config user.name "GitHub Actions Bot"
+            git config user.email "actions@github.com"
+            git commit -m "Initialize gh-pages branch"
+            git push origin gh-pages
+          fi
+          
+          # パッケージファイルをコピー
+          cp /tmp/helm-repo/"${PACKAGE_FILE}" .
+          
+          # index.yamlを生成/更新
+          helm repo index . --url "https://gitea.example.com/${GITHUB_REPOSITORY}/raw/branch/gh-pages"
+          
+          # コミットしてプッシュ
           git config user.name "GitHub Actions Bot"
           git config user.email "actions@github.com"
           git add "${PACKAGE_FILE}" index.yaml
-          git commit -m "chore: add ${CHART_NAME} v${WP_VERSION}"
+          git commit -m "chore: add ${CHART_NAME} v${WP_VERSION}" || echo "No changes to commit"
           git push origin gh-pages
-          echo "Helm repository updated"
+          
+          echo "Helm repository updated successfully"
+          
+          # mainブランチに戻る
+          git checkout main
 
       - name: Summary
         if: steps.check_update.outputs.update_needed == 'true'