diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 0c3c1a0a0a17029d373e10712151d257dc185ad9..510d3b227092fb2282cbf38ba80ddf3e3ca832a3 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -9,7 +9,7 @@ tests:
         GIT_DEPTH: 1
     script:
         - git submodule sync
-        - git submodule update --init --recursive
+        - git submodule update --init --recursive --depth=1
         - python3 -m pip install -r submodules/dagflow/requirements.txt
         - mkdir output
         - coverage run --source=. --omit=submodules/* -m pytest