diff --git a/scripts/ci/precheck_pep8.sh b/scripts/ci/precheck_pep8.sh
index fafa8a2de24..8026ec42b51 100755
--- a/scripts/ci/precheck_pep8.sh
+++ b/scripts/ci/precheck_pep8.sh
@@ -3,7 +3,7 @@
 set -e
 
 # install flake 8
-pip install -qqq flake8
+pip install -qqq flake8==3.5.0
 
 echo "Run flake8."
 flake8 --statistics --config=./.flake8