diff --git a/package/samplers/catcma/README.md b/package/samplers/catcma/README.md
index e850f921..019faa17 100644
--- a/package/samplers/catcma/README.md
+++ b/package/samplers/catcma/README.md
@@ -24,7 +24,7 @@ This figure is from https://arxiv.org/abs/2405.09962.
 ## Installation
 
 ```bash
-pip install -r requirements.txt
+pip install -r https://hub.optuna.org/samplers/catcma/requirements.txt
 ```
 
 ## Example
diff --git a/package/samplers/gp_pims/README.md b/package/samplers/gp_pims/README.md
index 2043c27c..89407345 100644
--- a/package/samplers/gp_pims/README.md
+++ b/package/samplers/gp_pims/README.md
@@ -34,7 +34,7 @@ license: "MIT License"
 ## Installation
 
 ```shell
-$ pip install -r requirements.txt
+$ pip install -r https://hub.optuna.org/samplers/gp_pims/requirements.txt
 ```
 
 ## Example
diff --git a/package/samplers/hebo/README.md b/package/samplers/hebo/README.md
index 1f0ad708..b15659d3 100644
--- a/package/samplers/hebo/README.md
+++ b/package/samplers/hebo/README.md
@@ -14,7 +14,7 @@ license: MIT License
 ## Installation
 
 ```bash
-pip install -r requirements.txt
+pip install -r https://hub.optuna.org/samplers/hebo/requirements.txt
 git clone git@github.com:huawei-noah/HEBO.git
 cd HEBO/HEBO
 pip install -e .
diff --git a/package/samplers/nelder_mead/README.md b/package/samplers/nelder_mead/README.md
index 36bec090..8d83f46f 100644
--- a/package/samplers/nelder_mead/README.md
+++ b/package/samplers/nelder_mead/README.md
@@ -20,7 +20,7 @@ This Nelder-Mead method implemenation employs the effective initialization metho
 ## Installation
 
 ```bash
-pip install -r https://raw.githubusercontent.com/optuna/optunahub-registry/main/package/samplers/nelder_mead/requirements.txt
+pip install -r https://hub.optuna.org/samplers/nelder_mead/requirements.txt
 ```
 
 ## Example
diff --git a/package/samplers/pfns4bo/README.md b/package/samplers/pfns4bo/README.md
index ffce0bae..e533ab5e 100644
--- a/package/samplers/pfns4bo/README.md
+++ b/package/samplers/pfns4bo/README.md
@@ -14,7 +14,7 @@ license: MIT License
 ## Installation
 
 ```bash
-pip install -r requirements.txt
+pip install -r https://hub.optuna.org/samplers/pfns4bo/requirements.txt
 ```
 
 ## Example
diff --git a/package/samplers/pfns4bo/example.ipynb b/package/samplers/pfns4bo/example.ipynb
index 5db920fc..018b85cc 100644
--- a/package/samplers/pfns4bo/example.ipynb
+++ b/package/samplers/pfns4bo/example.ipynb
@@ -42,8 +42,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "!curl -LO https://raw.githubusercontent.com/optuna/optunahub-registry/main/package/samplers/pfns4bo/requirements.txt\n",
-    "%pip install -q --progress-bar off -r requirements.txt\n",
+    "%pip install -q --progress-bar off -r https://hub.optuna.org/samplers/pfns4bo/requirements.txt\n",
     "%pip install -q --progress-bar off optunahub pfns4bo"
    ]
   },
diff --git a/package/samplers/plmbo/README.md b/package/samplers/plmbo/README.md
index e145855d..94e3f041 100644
--- a/package/samplers/plmbo/README.md
+++ b/package/samplers/plmbo/README.md
@@ -14,7 +14,7 @@ license: MIT License
 ## Installation
 
 ```sh
-pip install -r https://raw.githubusercontent.com/optuna/optunahub-registry/main/package/samplers/plmbo/requirements.txt
+pip install -r https://hub.optuna.org/samplers/plmbo/requirements.txt
 ```
 
 ## Example
diff --git a/package/samplers/uniform_design/README.md b/package/samplers/uniform_design/README.md
index 494c9a5f..c25ed67c 100644
--- a/package/samplers/uniform_design/README.md
+++ b/package/samplers/uniform_design/README.md
@@ -19,7 +19,7 @@ UD is a variety of design-of-experiment (DOE) methods, and it has better sample
 ## Installation
 
 ```shell
-$ pip install -r requirements.txt
+$ pip install -r https://hub.optuna.org/samplers/uniform_design/requirements.txt
 ```
 
 ## Example