Provided is a power control device, for a vehicle, that is excellent in efficient discharge of energy stored in a smoothing capacitor provided in the power control device. The level of an output voltage of a backup power supply unit for generating, from energy of the smoothing capacitor, drive power required for a discharge operation is switched so as to be equal to or higher than the level of the voltage of an auxiliary battery during the discharge operation. Accordingly, the power control device contributes to shortening of a time period for discharge of the smoothing capacitor, and contributes to reduction in the number of times of charging/discharging of the auxiliary battery since power supplied from the auxiliary battery can be reduced during the discharge operation.