diff --git a/.github/workflows/update-readme.yaml b/.github/workflows/update-readme.yaml
deleted file mode 100644
index 26ff4d86..00000000
--- a/.github/workflows/update-readme.yaml
+++ /dev/null
@@ -1,24 +0,0 @@
-on:
-    push:
-      branches:
-        - main
-
-jobs:
-    update-readme:
-      runs-on: ubuntu-latest
-      permissions:
-        contents: write
-      steps:
-        - uses: actions/checkout@v4
-        - uses: actions/setup-python@v5
-          with:
-            python-version: 3.11
-        - name: Install
-          run: |
-            python -m pip install -U pip
-            pip install --progress-bar off .
-        - run: python update_readme.py
-        - uses: stefanzweifel/git-auto-commit-action@v5
-          with:
-            commit_message: Update list in README
-            file_pattern: README.md
diff --git a/README.md b/README.md
index 1c9d03dd..cfdd0840 100644
--- a/README.md
+++ b/README.md
@@ -2,18 +2,4 @@
 OptunaHub Registry
 ==================
 
-# List of Packages
-
-## Samplers
-
-|Title|Description|
-| :---: | :---: |
-|[Demo Sampler](package/samplers/demo)|Demo Sampler of OptunaHub|
-|[Simulated Annealing Sampler](package/samplers/simulated_annealing)|Sampler based on simulated annealing algorithm.|
-|[Simple Sampler](package/samplers/simple)|An easy sampler base class to implement custom samplers.|
-
-## Visualization
-
-|Title|Description|
-| :---: | :---: |
-|[Plot Hypervolume History with Reference Point](package/visualization/plot_hypervolume_history_with_rp)|<img src="package/visualization/plot_hypervolume_history_with_rp/img/thumbnail.png" width="160px" height="120px" alt="Plot hypervolume history with the reference point information.">|
+__NOTICE: OptunaHub Registry is currently under preparation. We do not accept requests for package registration from the general public.__
diff --git a/update_readme.py b/update_readme.py
deleted file mode 100644
index 6991bb43..00000000
--- a/update_readme.py
+++ /dev/null
@@ -1,49 +0,0 @@
-from __future__ import annotations
-
-from enum import Enum
-from enum import unique
-import glob
-import os
-
-import frontmatter
-import mdutils
-
-
-@unique
-class HubCategory(Enum):
-    SAMPLER = "samplers"
-    VISUALIZATION = "visualization"
-
-
-def main() -> None:
-    mdFile = mdutils.MdUtils(file_name="README", title="OptunaHub Registry")
-    mdFile.new_header(level=1, title="List of Packages")
-    for category in HubCategory:
-        mdFile.new_header(level=2, title=category.value.title())
-        package_paths = glob.glob(f"package/{category.value}/**")
-        packages = ["Title", "Description"]
-        columns = len(packages)
-        for p in package_paths:
-            fm = frontmatter.load(f"{p}/README.md")
-            thumbnail = f"{p}/img/thumbnail.png"
-            if os.path.exists(thumbnail):
-                description = f'<img src="{thumbnail}" width="160px" height="120px" alt="{fm["description"]}">'
-            else:
-                description = fm["description"]
-            packages.extend(
-                [
-                    mdutils.tools.TextUtils.text_external_link(fm["title"], p),
-                    description,
-                ]
-            )
-        mdFile.new_table(
-            columns=columns,
-            rows=1 + len(package_paths),
-            text=packages,
-            text_align="center",
-        )
-    mdFile.create_md_file()
-
-
-if __name__ == "__main__":
-    main()