In a door control system, a reservation signal is transmitted when a user operates a mobile device and reserves opening a door, a control device transmits a reservation acceptance signal and starts transmitting a response request signal upon receipt of the reservation signal. When the mobile device receives the reservation acceptance signal, a mobile device memory stores information indicating that the reservation is accepted and authorized and a notification unit notifies the user of authorization. When the mobile device receives the response request signal, the mobile device transmits a response signal including the stored information indicating authorization. When the control device receives the response signal including the information indicating authorization in response to the response request signal, a controller performs at least one of unlocking or opening the door.