diff --git a/pkg/api/core/group/connection/v0/slack.go b/pkg/api/core/group/connection/v0/slack.go
index d76c7997..c992ddd4 100644
--- a/pkg/api/core/group/connection/v0/slack.go
+++ b/pkg/api/core/group/connection/v0/slack.go
@@ -43,7 +43,7 @@ func changeText(before, after core.Connection) string {
 
 	if after.Lock != nil {
 		if *before.Lock != *after.Lock {
-			if *after.Lock {
+			if !*after.Lock {
 				data += "ユーザ変更: 禁止 => 許可\n"
 			} else {
 				data += "ユーザ変更: 許可 => 禁止\n"
diff --git a/pkg/api/core/group/v0/slack.go b/pkg/api/core/group/v0/slack.go
index d3516a4c..69f2c315 100644
--- a/pkg/api/core/group/v0/slack.go
+++ b/pkg/api/core/group/v0/slack.go
@@ -45,7 +45,7 @@ func changeText(before, after core.Group) string {
 	}
 
 	if after.Lock != nil {
-		if *before.Lock != *after.Lock {
+		if !*before.Lock != *after.Lock {
 			if *after.Lock {
 				data += "ユーザ変更: 禁止 => 許可\n"
 			} else {