A power conversion device including sub-inverters, each connected in series with respective phase of a three-phase main inverter including a smoothing capacitor, which is fed from a power supply via a converter, as a DC input thereof, and feeds power to a load using the sum of outputs of the inverters. A manipulative quantity is determined so that the DC voltage at each of smoothing capacitors which is an input of each of the sub-inverters will follow a command value. The manipulative quantity is added to an output voltage command for the three-phase main inverter, and is subtracted from an output voltage command for the sub-inverters. Thus, power is shifted from the three-phase main inverter to the smoothing capacitors of the sub-inverters.