diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..482e926
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,6 @@
+[submodule "dev/groonga"]
+	path = dev/groonga
+	url = https://github.com/groonga/groonga.git
+[submodule "dev/arrow"]
+	path = dev/arrow
+	url = https://github.com/apache/arrow.git
diff --git a/dev/README.md b/dev/README.md
index 129ee64..f0d339e 100644
--- a/dev/README.md
+++ b/dev/README.md
@@ -20,11 +20,10 @@ sudo cmake --install build
 
 ```bash
 export LAUNCHPAD_UPLOADER_PGP_KEY=YOUR_PGP_KEY # e.g. export  LAUNCHPAD_UPLOADER_PGP_KEY=08D3564B7C6A9CAFBFF6A66791D18FCF079F8007
-git clone https://github.com/apache/arrow.git
-export APACHE_ARROW_REPOSITORY=${PWD}/arrow
-git clone https://github.com/groonga/groonga.git
-export GROONGA_REPOSITORY=${PWD}/groonga
 git clone git@github.com:enactic/openarm_can.git
 cd openarm_can
+git submodule update --recursive --init
+export APACHE_ARROW_REPOSITORY=${PWD}/dev/arrow
+export GROONGA_REPOSITORY=${PWD}/dev/groonga
 rake release NEW_VERSION=X.Y.Z # e.g. rake release 1.0.0
 ```
diff --git a/dev/arrow b/dev/arrow
new file mode 160000
index 0000000..4ed0916
--- /dev/null
+++ b/dev/arrow
@@ -0,0 +1 @@
+Subproject commit 4ed091623565a251a8058f6cada4340ce2f3f9b8
diff --git a/dev/groonga b/dev/groonga
new file mode 160000
index 0000000..cc4ae7e
--- /dev/null
+++ b/dev/groonga
@@ -0,0 +1 @@
+Subproject commit cc4ae7e3ecc241428922a40edb104a2be7b20ea8