A converter ECU (2) obtains allowable power total value including at least one of discharge allowable power total value ΣWout of discharge allowable power Wout1, Wout2 and charge allowable power total value ΣWin of charge allowable power Win1, Win2. Then, the converter ECU (2) determines which of the allowable power total value and an actual power value is greater, If the actual power value is smaller than the allowable power total value, the converter ECU (2) controls a converter (8-1) such that an input/output voltage value Vh attains a prescribed target voltage value, and at the same time controls a converter (8-2) such that a battery current value Ib2 attains a prescribed target current value.