When a certain period of time has elapsed since a direction retrieval unit received a control signal from an appliance controller, the direction retrieval unit instructs the microwave transmitter to transmit microwaves, and then instructs the microwave transmitter to perform scanning of the microwaves. When a notification signal receiver receives a notification signal from a remote controller, the direction retrieval unit instructs the microwave transmitter to stop the scanning of the microwaves. After this, the direction retrieval unit instructs a power controller to raise a power level of the microwaves. The direction retrieval unit determines whether or not the notification signal receiver receives from the notification signal transmitter of the remote controller at regular time intervals charging-in-progress signals indicating that charging is in progress and whether or not the notification signal receiver receives from the notification signal transmitter a charging-complete signal indicating that the charging is completed.