diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index b86d586..9636113 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -14,7 +14,7 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - name: setup rust toolchain
-        run: rustup toolchain install
+        run: rustup update && rustup toolchain install
       - uses: taiki-e/install-action@nextest
       - uses: taiki-e/install-action@mdbook
       - name: patch for gh-pages build
diff --git a/.github/workflows/pr.yml b/.github/workflows/pr.yml
index 2ef2348..449b68f 100644
--- a/.github/workflows/pr.yml
+++ b/.github/workflows/pr.yml
@@ -14,7 +14,7 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - name: setup rust toolchain
-        run: rustup show
+        run: rustup update && rustup toolchain install
       - uses: taiki-e/install-action@nextest
       - uses: taiki-e/install-action@mdbook
       - name: check and build