A power supply control unit in a power supply unit in a multi-functional peripheral turns off a PFC unit in a power-saving mode. If a return to a normal mode occurs, whether the PFC unit is to be turned on or not is controlled based on a cause of the return to the normal mode. If the PFC unit is not to be turned on or already has an ON state based on the occurrence of the return, the power supply control unit immediately causes power supply unit to start power supply based on the cause of return. If the PFC unit is turned on based on the occurrence of the return, the power supply control unit causes the power supply unit to start power supply based on the cause of return after a lapse of a delay time from the turning on of the PFC unit.