Provided is a power conversion device that converts power between DC units and three-phase AC. A first-phase conversion device, a second-phase conversion device, and a third-phase conversion device each include a DC/DC conversion circuit and a single-phase power conversion circuit. For each of the first-phase conversion device, the second-phase conversion device, and the third-phase conversion device, when an absolute value of a voltage target value for the AC exceeds DC voltage of each DC unit, a control unit causes the DC/DC conversion circuit to operate to achieve the absolute value of the voltage target value and causes the single-phase power conversion circuit to only perform necessary polarity inversion, and when the absolute value of the voltage target value is smaller than the DC voltage, the control unit stops operation of the DC/DC conversion circuit and causes the single-phase power conversion circuit to operate to achieve the voltage target value.