A failure in the activation, of a motor, caused by external noise superimposed on an induced voltage is reduced. A detection circuit is connected to a connection node provided between an upper-arm switching element and a lower-arm switching element, and detects the induced voltage of a fan motor before activation. The switching controller activates the fan motor in accordance with a result of detection by the detection circuit. While the detection circuit detects the induced voltage, the switching controller performs switching control which involves alternately turning ON and OFF of the lower-arm switching element.