diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 788eff3..d10d1bf 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,6 +1,6 @@
 name: CI_on_Ubuntu-latest
 
-on: [push]
+on: [push, pull_request]
 
 jobs:
   build:
diff --git a/.github/workflows/ci_ubuntu-16.04.yml b/.github/workflows/ci_ubuntu-16.04.yml
index 2021f9e..beffee3 100644
--- a/.github/workflows/ci_ubuntu-16.04.yml
+++ b/.github/workflows/ci_ubuntu-16.04.yml
@@ -1,6 +1,6 @@
 name: CI_on_ubuntu-16.04
 
-on: [push]
+on: [push, pull_request]
 
 jobs:
   build: