diff --git a/docs/notice-for-admins.md b/docs/notice-for-admins.md
index 5c2eb9b966..944b5703d8 100644
--- a/docs/notice-for-admins.md
+++ b/docs/notice-for-admins.md
@@ -31,11 +31,11 @@ psql (PostgreSQL) 16.1
 
 In this case, your PostgreSQL major version is `16`.
 
-There are official installation instructions for many operating systems on <https://pgroonga.github.io/install>, so please follow the instructions on this page. However, since many users are using Ubuntu, and there are no instructions for Arch Linux and Fedora, we explicitly list the instructions for Ubuntu, Arch Linux and Fedora here. Please keep in mind that this is not official information and the procedures may change.
+There are official installation instructions for many operating systems on <https://pgroonga.github.io/install>, so please follow the instructions on this page. However, since many users are using Ubuntu LTS or Debian, and there are no instructions for Arch Linux and Fedora, we explicitly list the instructions for Ubuntu LTS, Debian, Arch Linux and Fedora here. Please keep in mind that this is not official information and the procedures may change.
 
-##### Ubuntu
+##### Ubuntu LTS
 
-1. Install subdependencies and add apt repository
+1. Install subdependencies
     ```sh
     sudo apt install -y software-properties-common
     sudo add-apt-repository -y universe
@@ -43,14 +43,35 @@ There are official installation instructions for many operating systems on <http
     sudo apt install -y wget lsb-release
     wget https://packages.groonga.org/ubuntu/groonga-apt-source-latest-$(lsb_release --codename --short).deb
     sudo apt install -y -V ./groonga-apt-source-latest-$(lsb_release --codename --short).deb
-    echo "deb http://apt.postgresql.org/pub/repos/apt/ $(lsb_release --codename --short)-pgdg main" | sudo tee /etc/apt/sources.list.d/pgdg.list
-    wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | sudo apt-key add -
-    sudo apt update
     ```
-2. Install PGroonga
+2. Install PGroonga (replace `16` with your PostgreSQL version)
     ```sh
-    # Please replace "16" with your PostgreSQL major version
     sudo apt install postgresql-16-pgdg-pgroonga
+
+    # Depending on your PostgreSQL installation method,
+    # the above command may fail and you need to run
+    # the following instead:
+    # sudo apt install postgresql-16-pgroonga
+    ```
+
+##### Debian
+
+1. Install subdependencies
+    ```sh
+    sudo apt install -y -V ca-certificates lsb-release wget
+    wget https://apache.jfrog.io/artifactory/arrow/$(lsb_release --id --short | tr 'A-Z' 'a-z')/apache-arrow-apt-source-latest-$(lsb_release --codename --short).deb
+    sudo apt install -y -V ./apache-arrow-apt-source-latest-$(lsb_release --codename --short).deb
+    wget https://packages.groonga.org/debian/groonga-apt-source-latest-$(lsb_release --codename --short).deb
+    sudo apt install -y -V ./groonga-apt-source-latest-$(lsb_release --codename --short).deb
+    ```
+2. Install PGroonga (replace `16` with your PostgreSQL version)
+    ```sh
+    sudo apt install postgresql-16-pgdg-pgroonga
+
+    # Depending on your PostgreSQL installation method,
+    # the above command may fail and you need to run
+    # the following instead:
+    # sudo apt install postgresql-16-pgroonga
     ```
 
 ##### Arch Linux