An image communicating apparatus which includes a telephone control unit configured to control a telephone includes a controller with a main CPU, and a power supply control unit configured to control power supply. When transiting to a sleep mode, the controller stops power supply to itself, and also supplies power to the telephone control unit so that the telephone control unit can detect at least off-hook of the telephone. When the off-hook of the telephone is detected in the sleep mode, the telephone control unit starts power supply to the controller, holds a dial signal input while the controller is activated, and transmits the held dial signal to the controller upon completion of activation of the controller.