diff --git a/.github/workflows/CI.yml b/.github/workflows/CI.yml
index d06020d51..69343f714 100644
--- a/.github/workflows/CI.yml
+++ b/.github/workflows/CI.yml
@@ -97,7 +97,7 @@ jobs:
         uses: PyO3/maturin-action@v1
         with:
           command: sdist
-          args: --out dist --manifest-path crates/voicevox_core_python_api/Cargo.toml
+          args: --out dist --locked --manifest-path crates/voicevox_core_python_api/Cargo.toml
       - name: Upload sdist
         uses: actions/upload-artifact@v3
         with: