A power conversion apparatus includes two power conversion circuits, two direct-current inductors, and a pulse-width-modulation control circuit. One of the two power conversion circuits is connected in parallel to a direct-current load or a single-phase alternating-current load, and the other of the two power conversion circuits is connected in parallel to a three-phase alternating-current load. The two power conversion circuits are connected in reverse polarity to each other via the two direct-current inductors. The pulse-width-modulation control circuit pulse-width-modulates the two power conversion circuits, allows switching between the two power conversion circuits, and realizes a bidirectional step-up/down operation between the direct-current load or single-phase alternating-current load and the three-phase alternating-current load.