Entry of a synchronous speed of a rotor can be facilitated by increasing a starting torque by adjusting a magnetization application time for magnetizing the rotor according to whether or not a starting capacitor is used. The present invention includes: a control unit that outputs a control signal for controlling an application time of a magnetizing current according to whether or not a starting capacitor is used; and a switch that supplies power to an exciting coil according to the control signal outputted from the control unit.