A plurality of switching units are provided, and a controller performs control in an antiphase manner to approximately synchronize a rise of a control signal applied to one of the switching units with a fall of a control signal for switching applied to any one of the other switching units and synchronize a fall of the control signal applied to the one of the switching units with a rise of the control signal for switching applied to the any one of the other switching units. When control in an antiphase manner is disabled, control is performed to prevent rises or falls from coinciding with each other between the switching units. Output signals from the switching units are input to rectifiers and are combined by a combiner to become an output signal.