A first conversion circuit switches a magnitude of a voltage generated between a first output point and a reference potential point in three stages. The second conversion circuit switches a magnitude of a voltage generated between the reference potential point and a second output point in three stages. The third conversion circuit includes first to fourth switches in a full bridge configuration and converts a voltage generated between the first output point and the second output point into an alternate current voltage and outputs the alternate current voltage. The third conversion circuit forms a current path including inductors between the first output point and the second output point during a start time period from a start of supplying power from a direct current power supply until a first capacitor and a second capacitor are charged to a specified voltage.