An electronic device has a connecting unit configured to connect to an external device by cable and receive external power from the external device, and a control unit configured to execute a predetermined function using the external power. The electronic device logically determines a power supply capability of the external device connected to the connecting unit, and determines whether the external device is capable of power supply at the logically determined power supply capability. If it is determined that the external device is not capable of power supply at the logically determined power supply capability, a prohibited state in which the predetermined function cannot be executed using the external power is set to the control unit.