An object of the present invention is to synchronize PWM between individual phases of an IPM, so that the IPM has a simplified-scale circuit. An IPM according to the present invention includes a DC-DC converter including a multi-phase arm having a plurality of phase arms connected in parallel on a secondary side, a secondary-wire-voltage detection circuit configured to detect a secondary wire voltage in each phase arm of the DC-DC converter, and a synchronization-signal generation circuit configured to generate a synchronization signal in each phase arm on the basis of the behavior of the secondary wire voltage.