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diff --git a/ui/s3hub/command.go b/ui/s3hub/command.go
index c957d6d..d83e820 100644
--- a/ui/s3hub/command.go
+++ b/ui/s3hub/command.go
@@ -2,7 +2,8 @@ package s3hub
 
 import (
 	"context"
-	"math/rand"
+	"crypto/rand"
+	"math/big"
 	"time"
 
 	tea "github.com/charmbracelet/bubbletea"
@@ -36,8 +37,14 @@ type deleteS3BucketMsg struct {
 
 // deleteS3BucketCmd deletes the S3 bucket.
 func deleteS3BucketCmd(ctx context.Context, app *di.S3App, bucket model.Bucket) tea.Cmd {
-	d := time.Millisecond * time.Duration(rand.Intn(500)) //nolint:gosec
-	return tea.Tick(d, func(t time.Time) tea.Msg {
+	d, err := rand.Int(rand.Reader, big.NewInt(500))
+	if err != nil {
+		// エラーのハンドリング
+		return tea.Quit
+	}
+	delay := time.Millisecond * time.Duration(d.Int64())
+
+	return tea.Tick(delay, func(t time.Time) tea.Msg {
 		_, err := app.S3BucketDeleter.DeleteS3Bucket(ctx, &usecase.S3BucketDeleterInput{
 			Bucket: bucket,
 		})