diff --git a/.github/workflows/CI_rs.yml b/.github/workflows/CI_rs.yml
index 136d0fec..662ca621 100644
--- a/.github/workflows/CI_rs.yml
+++ b/.github/workflows/CI_rs.yml
@@ -33,33 +33,34 @@ jobs:
       - name: Run clippy
         run: cargo clippy --workspace --all-targets -- -D warnings
 
-  test:
-    name: Test
-    runs-on: ubuntu-22.04
-    env:
-      # CI release tests don't need DWARF debug info, and disabling it keeps
-      # target artifacts small enough to avoid runner disk exhaustion on cache misses.
-      CARGO_PROFILE_RELEASE_DEBUG: 0
-    steps:
-      - uses: actions/checkout@v4
+  # testジョブ全体を無効化
+  # test:
+  #   name: Test
+  #   runs-on: ubuntu-22.04
+  #   env:
+  #     # CI release tests don't need DWARF debug info, and disabling it keeps
+  #     # target artifacts small enough to avoid runner disk exhaustion on cache misses.
+  #     CARGO_PROFILE_RELEASE_DEBUG: 0
+  #   steps:
+  #     - uses: actions/checkout@v4
 
-      - name: Install HDF5
-        run: sudo apt-get update && sudo apt-get install -y libhdf5-dev
+  #     - name: Install HDF5
+  #       run: sudo apt-get update && sudo apt-get install -y libhdf5-dev
 
-      - name: Install Rust
-        uses: dtolnay/rust-toolchain@stable
+  #     - name: Install Rust
+  #       uses: dtolnay/rust-toolchain@stable
 
-      - uses: taiki-e/install-action@nextest
+  #     - uses: taiki-e/install-action@nextest
 
-      - uses: Swatinem/rust-cache@v2
+  #     - uses: Swatinem/rust-cache@v2
 
-      # tensor4all-hdf5 is kept out of nextest because its dlopen-based tests
-      # fail under nextest's per-process execution model.
-      - name: Run tests (non-HDF5)
-        run: cargo nextest run --release --workspace --exclude tensor4all-hdf5
+  #     # tensor4all-hdf5 is kept out of nextest because its dlopen-based tests
+  #     # fail under nextest's per-process execution model.
+  #     - name: Run tests (non-HDF5)
+  #       run: cargo nextest run --release --workspace --exclude tensor4all-hdf5
 
-      - name: Run HDF5 tests
-        run: cargo test --release -p tensor4all-hdf5
+  #     - name: Run HDF5 tests
+  #       run: cargo test --release -p tensor4all-hdf5
 
   coverage:
     name: Coverage
@@ -86,7 +87,7 @@ jobs:
     runs-on: ubuntu-latest
     needs:
       - lint
-      - test
+      #- test
       - coverage
     if: always()
     steps:
diff --git a/.github/workflows/CI_rs_selfhost.yml b/.github/workflows/CI_rs_selfhost.yml
new file mode 100644
index 00000000..8eb01e01
--- /dev/null
+++ b/.github/workflows/CI_rs_selfhost.yml
@@ -0,0 +1,66 @@
+name: CI_rs_selfhost
+
+on:
+  pull_request:
+    branches: [main]
+
+permissions:
+  contents: read
+
+concurrency:
+  group: ci-pr-${{ github.event.pull_request.number }}
+  cancel-in-progress: true
+
+jobs:
+  # fork からの PR: GitHub-hosted runner で通常 CI
+  ci-fork:
+    name: CI (fork PR / github-hosted)
+    if: github.event.pull_request.head.repo.full_name != github.repository
+    runs-on: ubuntu-22.04
+    env:
+      # CI release tests don't need DWARF debug info, and disabling it keeps
+      # target artifacts small enough to avoid runner disk exhaustion on cache misses.
+      CARGO_PROFILE_RELEASE_DEBUG: 0
+    steps:
+      - uses: actions/checkout@v6
+
+      - name: Install HDF5
+        run: sudo apt-get update && sudo apt-get install -y libhdf5-dev
+
+      - name: Install Rust
+        uses: dtolnay/rust-toolchain@stable
+
+      - uses: taiki-e/install-action@nextest
+
+      - uses: Swatinem/rust-cache@v2
+
+      # tensor4all-hdf5 is kept out of nextest because its dlopen-based tests
+      # fail under nextest's per-process execution model.
+      - name: Run tests (non-HDF5)
+        run: cargo nextest run --release --workspace --exclude tensor4all-hdf5
+
+      - name: Run HDF5 tests
+        run: cargo test --release -p tensor4all-hdf5
+
+  # PRs from the same repository: run heavy CI on self-hosted runner
+  ci-maintainer:
+    name: CI (same-repo PR / self-hosted heavy)
+    if: github.event.pull_request.head.repo.full_name == github.repository
+    runs-on: [self-hosted, linux, x64]
+    env:
+      CARGO_TARGET_DIR: ${{ github.workspace }}/../target
+      CARGO_PROFILE_RELEASE_DEBUG: 0
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+
+      # 必要に応じてセットアップを追加
+      - uses: dtolnay/rust-toolchain@stable
+
+      - uses: taiki-e/install-action@nextest
+
+      - name: Run tests (non-HDF5)
+        run: cargo nextest run --release --workspace --exclude tensor4all-hdf5
+
+      - name: Run HDF5 tests
+        run: cargo test --release -p tensor4all-hdf5