A control system includes a control device, a controller, a plurality of user mobile devices, and a manager mobile device. Initial first identification information picked up by each user mobile device is sent to the manager mobile device, is authenticated, and is encoded. Every time a user mobile device is connected to the controller for opening the control device, a holder of the user mobile device is requested to input an instant first identification information. After decoding by a decoding key, the controller identifies whether the instant first identification information is identical to the authenticated initial first identification information. The identification result is used to decide whether the control device should be set to be an open state.