diff --git a/requirements.txt b/requirements.txt
index d67ce05..5e10f9b 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -12,7 +12,7 @@ konlpy==0.5.1
 ktkws==1.0.1
 MarkupSafe==1.1.1
 numpy==1.16.2
-protobuf==3.7.0
+protobuf==3.15.0
 PyAudio==0.2.11
 PyYAML==5.1
 requests==2.21.0