diff --git a/handler.go b/handler.go
index be06818..3751c04 100644
--- a/handler.go
+++ b/handler.go
@@ -116,13 +116,13 @@ func (h *SlackHandler) WithGroup(name string) slog.Handler {
 }
 
 func (h *SlackHandler) postMessage(message *slack.WebhookMessage) error {
-	if h.option.WebhookURL != "" {
-		return slack.PostWebhook(h.option.WebhookURL, message)
-	}
-
 	ctx, cancel := context.WithTimeout(context.Background(), h.option.Timeout)
 	defer cancel()
 
+	if h.option.WebhookURL != "" {
+		return slack.PostWebhookContext(ctx, h.option.WebhookURL, message)
+	}
+
 	_, _, err := slack.
 		New(h.option.BotToken).
 		PostMessageContext(