diff --git a/composer.json b/composer.json
index c7780cc..0828f9e 100644
--- a/composer.json
+++ b/composer.json
@@ -12,7 +12,7 @@
     "require": {
         "php": ">=8.1",
         "ext-mbstring": "*",
-        "dragonmantank/cron-expression": "^2.0 || ^3.0"
+        "dragonmantank/cron-expression": "^2.3 || ^3.0"
     },
     "require-dev": {
         "infection/infection": "^0.27.11",
diff --git a/src/CronJob.php b/src/CronJob.php
index 40b0dd1..150fad8 100644
--- a/src/CronJob.php
+++ b/src/CronJob.php
@@ -4,13 +4,20 @@
 
 namespace Setono\CronBuilder;
 
+use Cron\CronExpression;
+
 final class CronJob implements \Stringable
 {
+    public readonly string $schedule;
+
     public function __construct(
-        public readonly string $schedule,
+        string $schedule,
         public readonly string $command,
         public readonly ?string $description = null,
     ) {
+        new CronExpression($schedule);
+
+        $this->schedule = $schedule;
     }
 
     public function toString(): string