A power converter includes single-phase subinverters (2a to 2c) connected in series to each phase of a three-phase main inverter (1) using a smoothing capacitor (6) which receives power supply from a power source (11) through a converter (5) as a DC input to apply the power supply to a load (12) by the sum of the outputs of the inverter (1) and the single-phase subinverters (2a to 2c).The power converter determines a manipulated variable so that the DC voltages of smoothing capacitors (3a to 3c) which become inputs of the single-phase subinverters (2a to 2c) follow a command value, adds the manipulated variable to the command value of the output voltage of the three-phase main inverter (1), and subtracts the manipulated variable from the command value of the output voltages of the single-phase subinverters (2a to 2c). Thereby, a power shift takes place from the three-phase main inverter (1) to the smoothing capacitors (3a to 3c) of the single-phase subinverters (2a to 2c).