diff --git a/CHANGELOG.md b/CHANGELOG.md
index c397f223..7930830d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,10 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
 
+### Changed
+
+- Update fluent-bit image to 3.1.7 [#738](https://github.com/cybozu-go/moco/pull/738)
+
 ## [0.23.2] - 2024-07-02
 
 ### Fixed
diff --git a/version.go b/version.go
index 1370b471..7f6986a5 100644
--- a/version.go
+++ b/version.go
@@ -5,7 +5,7 @@ const (
 	Version = "0.23.2"
 
 	// FluentBitImage is the image for slow-log sidecar container.
-	FluentBitImage = "ghcr.io/cybozu-go/moco/fluent-bit:3.0.2.1"
+	FluentBitImage = "ghcr.io/cybozu-go/moco/fluent-bit:3.1.7.1"
 
 	// ExporterImage is the image for mysqld_exporter sidecar container.
 	ExporterImage = "ghcr.io/cybozu-go/moco/mysqld_exporter:0.15.1.2"