diff --git a/Dockerfile b/Dockerfile
index 0d3ac8a..d2c5a3f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM golang:1.21.5-bullseye
+FROM golang:1.21.6-bullseye
 
 # `debconf: delaying package configuration, since apt-utils is not installed` を抑止する
 ENV DEBCONF_NOWARNINGS yes
diff --git a/README.md b/README.md
index 54caf5c..019f1d2 100644
--- a/README.md
+++ b/README.md
@@ -3,11 +3,11 @@
 ## build
 
 ```
-docker build --platform linux/amd64 -t pacificporter/golang:1.21.5-bullseye-18.18.0 .
+docker build --platform linux/amd64 -t pacificporter/golang:1.21.6-bullseye-18.18.0 .
 ```
 
 ## push
 
 ```
-docker push pacificporter/golang:1.21.5-bullseye-18.18.0
+docker push pacificporter/golang:1.21.6-bullseye-18.18.0
 ```