diff --git a/requirements.txt b/requirements.txt
index f266dc1..288952b 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,4 @@
-certifi==2017.7.27.1
+certifi==2022.12.7
 chainer==2.1.0
 chardet==3.0.4
 cupy==1.0.3