An inverter converts direct-current power to alternating-current power by operations of a plurality of switching elements under a PWM control, and supplies the alternating-current power to an alternating-current electric motor. A feedback control computation unit of an inverter control unit uses current values acquired from current sensors detecting a current flowing to the alternating-current electric motor and a rotation angle of the alternating-current electric motor to perform a control computation in a (N/2) cycle (N is a natural number) of a triangular wave carrier of the PWM control. At the acquisition of the current values detected by the current sensors, an average acquisition unit acquires an average of current values in a carrier half cycle as a period between a peak and a valley of the carrier, or acquires a current value regarded as an average of the current values at an acquirable timing.