diff --git a/.github/workflows/build-docs.yml b/.github/workflows/build-docs.yml
index 90baa9a6b..79ed1de52 100644
--- a/.github/workflows/build-docs.yml
+++ b/.github/workflows/build-docs.yml
@@ -27,7 +27,7 @@ jobs:
         uses: ./.github/actions/prepare_python
 
       - name: <Build> Make documents
-        run: PYTHONPATH=. python build_util/make_docs.py
+        run: PYTHONPATH=. python tools/make_docs.py
 
       - name: <Deploy> Deploy documents to GitHub Pages
         uses: peaceiris/actions-gh-pages@v4
diff --git a/.github/workflows/build-engine-container.yml b/.github/workflows/build-engine-container.yml
index 86c8215c1..f37d14fe5 100644
--- a/.github/workflows/build-engine-container.yml
+++ b/.github/workflows/build-engine-container.yml
@@ -120,7 +120,7 @@ jobs:
       - name: <Build> Merge VOICEVOX RESOURCE
         env:
           DOWNLOAD_RESOURCE_PATH: download/resource
-        run: bash build_util/process_voicevox_resource.bash
+        run: bash tools/process_voicevox_resource.bash
 
       - name: <Build/Deploy> Build and Deploy Docker image
         uses: docker/build-push-action@v5
diff --git a/.github/workflows/build-engine-package.yml b/.github/workflows/build-engine-package.yml
index f979c3af6..566582980 100644
--- a/.github/workflows/build-engine-package.yml
+++ b/.github/workflows/build-engine-package.yml
@@ -290,7 +290,7 @@ jobs:
 
       - name: <Setup> Prepare custom PyInstaller
         if: startsWith(matrix.os, 'windows-')
-        run: ./build_util/modify_pyinstaller.bash
+        run: ./tools/modify_pyinstaller.bash
 
       - name: <Setup> Download pyopenjtalk dictionary
         run: |
@@ -409,7 +409,7 @@ jobs:
       - name: <Build> Merge RESOURCE
         env:
           DOWNLOAD_RESOURCE_PATH: download/resource
-        run: bash build_util/process_voicevox_resource.bash
+        run: bash tools/process_voicevox_resource.bash
 
       # VOICEVOX CORE
       - name: <Setup> Prepare CORE cache
@@ -441,7 +441,7 @@ jobs:
       - name: <Build> Generate licenses.json
         run: |
           OUTPUT_LICENSE_JSON_PATH=resources/engine_manifest_assets/dependency_licenses.json \
-          bash build_util/create_venv_and_generate_licenses.bash
+          bash tools/create_venv_and_generate_licenses.bash
           # FIXME: VOICEVOX (editor) cannot build without licenses.json
           cp resources/engine_manifest_assets/dependency_licenses.json licenses.json
 
@@ -547,7 +547,7 @@ jobs:
 
       - name: <Build> Code signing
         if: github.event.inputs.code_signing == 'true' && startsWith(matrix.os, 'windows-')
-        run: bash build_util/codesign.bash "dist/run/run.exe"
+        run: bash tools/codesign.bash "dist/run/run.exe"
         env:
           ESIGNERCKA_USERNAME: ${{ secrets.ESIGNERCKA_USERNAME }}
           ESIGNERCKA_PASSWORD: ${{ secrets.ESIGNERCKA_PASSWORD }}
diff --git a/.github/workflows/test-engine-container.yml b/.github/workflows/test-engine-container.yml
index b84276b43..91163221a 100644
--- a/.github/workflows/test-engine-container.yml
+++ b/.github/workflows/test-engine-container.yml
@@ -85,4 +85,4 @@ jobs:
           exit 1
 
       - name: <Test> Test ENGINE application docker container
-        run: python build_util/check_release_build.py --skip_run_process --dist_dir dist/
+        run: python tools/check_release_build.py --skip_run_process --dist_dir dist/
diff --git a/.github/workflows/test-engine-package.yml b/.github/workflows/test-engine-package.yml
index 025c5ee4e..3e9dc1a18 100644
--- a/.github/workflows/test-engine-package.yml
+++ b/.github/workflows/test-engine-package.yml
@@ -82,4 +82,4 @@ jobs:
         run: chmod +x dist/run
 
       - name: <Test> Test ENGINE package
-        run: python build_util/check_release_build.py --dist_dir dist/
+        run: python tools/check_release_build.py --dist_dir dist/
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index af4d06c56..7df025809 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -57,7 +57,7 @@ jobs:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
       - name: <Test> Check licenses
-        run: OUTPUT_LICENSE_JSON_PATH=/dev/null bash build_util/create_venv_and_generate_licenses.bash
+        run: OUTPUT_LICENSE_JSON_PATH=/dev/null bash tools/create_venv_and_generate_licenses.bash
 
       - name: <Test> Test names by checking typo
         if: matrix.os == 'ubuntu-20.04'
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index ef2784e02..5ab1629c7 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -305,7 +305,7 @@ safety check -r requirements.txt -r requirements-dev.txt -r requirements-build.t
 
 ```bash
 OUTPUT_LICENSE_JSON_PATH=licenses.json \
-bash build_util/create_venv_and_generate_licenses.bash
+bash tools/create_venv_and_generate_licenses.bash
 
 # モックでビルドする場合
 pyinstaller --noconfirm run.spec
@@ -328,7 +328,7 @@ fork したリポジトリで Actions を ON にし、workflow_dispatch で`buil
 次のコマンドで API ドキュメントを手動で作成することができます。
 
 ```bash
-PYTHONPATH=. python build_util/make_docs.py
+PYTHONPATH=. python tools/make_docs.py
 ```
 
 ## GitHub Actions
diff --git a/Dockerfile b/Dockerfile
index 5b0d59b72..b86551232 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -231,8 +231,8 @@ ADD ./voicevox_engine /opt/voicevox_engine/voicevox_engine
 ADD ./docs /opt/voicevox_engine/docs
 ADD ./run.py ./presets.yaml ./engine_manifest.json /opt/voicevox_engine/
 ADD ./resources /opt/voicevox_engine/resources
-ADD ./build_util/generate_licenses.py /opt/voicevox_engine/build_util/
-ADD ./build_util/licenses /opt/voicevox_engine/build_util/licenses
+ADD ./tools/generate_licenses.py /opt/voicevox_engine/tools/
+ADD ./tools/licenses /opt/voicevox_engine/tools/licenses
 
 # Replace version
 ARG VOICEVOX_ENGINE_VERSION=latest
@@ -254,7 +254,7 @@ RUN <<EOF
     gosu user /opt/python/bin/pip3 install -r /tmp/requirements.txt
     # requirements-dev.txt でバージョン指定されている pip-licenses をインストールする
     gosu user /opt/python/bin/pip3 install "$(grep pip-licenses /tmp/requirements-dev.txt | cut -f 1 -d ';')"
-    gosu user /opt/python/bin/python3 build_util/generate_licenses.py > /opt/voicevox_engine/resources/engine_manifest_assets/dependency_licenses.json
+    gosu user /opt/python/bin/python3 tools/generate_licenses.py > /opt/voicevox_engine/resources/engine_manifest_assets/dependency_licenses.json
     cp /opt/voicevox_engine/resources/engine_manifest_assets/dependency_licenses.json /opt/voicevox_engine/licenses.json
 EOF
 
diff --git a/README.md b/README.md
index 8c03578b8..b5bd9d692 100644
--- a/README.md
+++ b/README.md
@@ -573,7 +573,7 @@ DYLD_LIBRARY_PATH="/path/to/onnx" python run.py --voicelib_dir="/path/to/voicevo
 python -m pip install -r requirements-build.txt
 
 OUTPUT_LICENSE_JSON_PATH=licenses.json \
-bash build_util/create_venv_and_generate_licenses.bash
+bash tools/create_venv_and_generate_licenses.bash
 
 # モックでビルドする場合
 pyinstaller --noconfirm run.spec
@@ -719,7 +719,7 @@ VOICEVOX エディターにうまく読み込ませられないときは、エ
 次のコマンドで API ドキュメントを手動で作成することができます。
 
 ```bash
-PYTHONPATH=. python build_util/make_docs.py
+PYTHONPATH=. python tools/make_docs.py
 ```
 
 ### GitHub Actions
diff --git a/build_util/check_release_build.py b/tools/check_release_build.py
similarity index 100%
rename from build_util/check_release_build.py
rename to tools/check_release_build.py
diff --git a/build_util/codesign.bash b/tools/codesign.bash
similarity index 100%
rename from build_util/codesign.bash
rename to tools/codesign.bash
diff --git a/build_util/create_venv_and_generate_licenses.bash b/tools/create_venv_and_generate_licenses.bash
similarity index 91%
rename from build_util/create_venv_and_generate_licenses.bash
rename to tools/create_venv_and_generate_licenses.bash
index 4e3d25fe8..09d9154d8 100644
--- a/build_util/create_venv_and_generate_licenses.bash
+++ b/tools/create_venv_and_generate_licenses.bash
@@ -21,7 +21,7 @@ fi
 pip install -r requirements.txt
 # requirements-dev.txt でバージョン指定されている pip-licenses をインストールする
 pip install "$(grep pip-licenses requirements-dev.txt | cut -f 1 -d ';')"
-python build_util/generate_licenses.py > "${OUTPUT_LICENSE_JSON_PATH}"
+python tools/generate_licenses.py > "${OUTPUT_LICENSE_JSON_PATH}"
 
 deactivate
 
diff --git a/build_util/generate_licenses.py b/tools/generate_licenses.py
similarity index 97%
rename from build_util/generate_licenses.py
rename to tools/generate_licenses.py
index f7317e46c..d7d0e9d53 100644
--- a/build_util/generate_licenses.py
+++ b/tools/generate_licenses.py
@@ -141,21 +141,21 @@ def generate_licenses() -> list[License]:
             package_name="Open JTalk",
             package_version="1.11",
             license_name="Modified BSD license",
-            license_text="build_util/licenses/open_jtalk/COPYING",
+            license_text="tools/licenses/open_jtalk/COPYING",
             license_text_type="local_address",
         ),
         License(
             package_name="MeCab",
             package_version=None,
             license_name="Modified BSD license",
-            license_text="build_util/licenses/open_jtalk/mecab/COPYING",
+            license_text="tools/licenses/open_jtalk/mecab/COPYING",
             license_text_type="local_address",
         ),
         License(
             package_name="NAIST Japanese Dictionary",
             package_version=None,
             license_name="Modified BSD license",
-            license_text="build_util/licenses//open_jtalk/mecab-naist-jdic/COPYING",
+            license_text="tools/licenses//open_jtalk/mecab-naist-jdic/COPYING",
             license_text_type="local_address",
         ),
         License(
@@ -257,7 +257,7 @@ def generate_licenses() -> list[License]:
             package_name="mpg123",
             package_version="1.30.2",
             license_name="LGPL-2.1 license",
-            license_text="build_util/licenses/mpg123/COPYING",
+            license_text="tools/licenses/mpg123/COPYING",
             license_text_type="local_address",
         ),
         # liblame
@@ -277,7 +277,7 @@ def generate_licenses() -> list[License]:
             package_name="CUDA Toolkit",
             package_version="11.8.0",
             license_name=None,
-            license_text="build_util/licenses/cuda/EULA.txt",
+            license_text="tools/licenses/cuda/EULA.txt",
             license_text_type="local_address",
         ),
         # license text from cuDNN v8.9.2 (June 1st, 2023), for CUDA 11.x, cuDNN Library for Windows # noqa: B950
@@ -288,7 +288,7 @@ def generate_licenses() -> list[License]:
             package_name="cuDNN",
             package_version="8.9.2",
             license_name=None,
-            license_text="build_util/licenses/cudnn/LICENSE",
+            license_text="tools/licenses/cudnn/LICENSE",
             license_text_type="local_address",
         ),
     ]
diff --git a/build_util/get_cost_candidates.py b/tools/get_cost_candidates.py
similarity index 97%
rename from build_util/get_cost_candidates.py
rename to tools/get_cost_candidates.py
index 15de04175..168854d96 100644
--- a/build_util/get_cost_candidates.py
+++ b/tools/get_cost_candidates.py
@@ -3,7 +3,7 @@
 引数のnaist_jdic_pathには、open_jtalkのsrc/mecab-naist-jdic/naist-jdic.csvを指定してください。
 
 実行例:
-python build_util/get_cost_candidates.py --naist_jdic_path=/path/to/naist-jdic.csv \
+python tools/get_cost_candidates.py --naist_jdic_path=/path/to/naist-jdic.csv \
     --pos=名詞 \
     --pos_detail_1=固有名詞 \
     --pos_detail_2=一般 \
diff --git a/build_util/licenses/cuda/EULA.txt b/tools/licenses/cuda/EULA.txt
similarity index 100%
rename from build_util/licenses/cuda/EULA.txt
rename to tools/licenses/cuda/EULA.txt
diff --git a/build_util/licenses/cudnn/LICENSE b/tools/licenses/cudnn/LICENSE
similarity index 100%
rename from build_util/licenses/cudnn/LICENSE
rename to tools/licenses/cudnn/LICENSE
diff --git a/build_util/licenses/mpg123/COPYING b/tools/licenses/mpg123/COPYING
similarity index 100%
rename from build_util/licenses/mpg123/COPYING
rename to tools/licenses/mpg123/COPYING
diff --git a/build_util/licenses/open_jtalk/COPYING b/tools/licenses/open_jtalk/COPYING
similarity index 100%
rename from build_util/licenses/open_jtalk/COPYING
rename to tools/licenses/open_jtalk/COPYING
diff --git a/build_util/licenses/open_jtalk/mecab-naist-jdic/COPYING b/tools/licenses/open_jtalk/mecab-naist-jdic/COPYING
similarity index 100%
rename from build_util/licenses/open_jtalk/mecab-naist-jdic/COPYING
rename to tools/licenses/open_jtalk/mecab-naist-jdic/COPYING
diff --git a/build_util/licenses/open_jtalk/mecab/COPYING b/tools/licenses/open_jtalk/mecab/COPYING
similarity index 100%
rename from build_util/licenses/open_jtalk/mecab/COPYING
rename to tools/licenses/open_jtalk/mecab/COPYING
diff --git a/build_util/licenses/world/LICENSE.txt b/tools/licenses/world/LICENSE.txt
similarity index 100%
rename from build_util/licenses/world/LICENSE.txt
rename to tools/licenses/world/LICENSE.txt
diff --git a/build_util/make_docs.py b/tools/make_docs.py
similarity index 100%
rename from build_util/make_docs.py
rename to tools/make_docs.py
diff --git a/build_util/merge_update_infos.py b/tools/merge_update_infos.py
similarity index 100%
rename from build_util/merge_update_infos.py
rename to tools/merge_update_infos.py
diff --git a/build_util/modify_pyinstaller.bash b/tools/modify_pyinstaller.bash
similarity index 100%
rename from build_util/modify_pyinstaller.bash
rename to tools/modify_pyinstaller.bash
diff --git a/build_util/process_voicevox_resource.bash b/tools/process_voicevox_resource.bash
similarity index 96%
rename from build_util/process_voicevox_resource.bash
rename to tools/process_voicevox_resource.bash
index 28572fb83..086557209 100644
--- a/build_util/process_voicevox_resource.bash
+++ b/tools/process_voicevox_resource.bash
@@ -19,7 +19,7 @@ jq -s '.[0] * .[1]' engine_manifest.json "${DOWNLOAD_RESOURCE_PATH}/engine/engin
 mv engine_manifest.json.tmp engine_manifest.json
 
 # エンジンとリソースの更新情報を統合する
-python build_util/merge_update_infos.py \
+python tools/merge_update_infos.py \
     resources/engine_manifest_assets/update_infos.json \
     "${DOWNLOAD_RESOURCE_PATH}/engine/engine_manifest_assets/update_infos.json" \
     resources/engine_manifest_assets/update_infos.json