diff --git a/build_depends-humble.repos b/build_depends-humble.repos
index cec19257b..966bd1c01 100644
--- a/build_depends-humble.repos
+++ b/build_depends-humble.repos
@@ -1,4 +1,9 @@
 repositories:
+  sync_tooling_msgs:
+    type: git
+    url: https://github.com/tier4/sync_tooling_msgs.git
+    version: main
+
   # TODO(TIER IV): During the transition period of Agnocast introduction,
   # the Agnocast ROS packages are provided as a source build.
   # Once the transition stabilizes, use the packages released from the official ROS repository.