A control system including a controller system and a support device is provided. The controller system controls a control target. The support device supports setting of the controller system. The support device includes a system-configuration input part, a threat analysis database, a threat-scenario creating part, a countermeasure database, a countermeasure creating part, and a security setting part. The countermeasure creating part creates a countermeasure scenario containing a countermeasure for each of protected assets of the controller system according to a threat scenario and countermeasures of the countermeasure database.