PURPOSE: To reduce harmonic waves by connecting a main switch circuit and a main switch circuit having a circuit configuration similar to that of the previous main switch circuit to a current balanced reactor.

CONSTITUTION: A main switch circuit B having the same phase as that of a main switch circuit A is provided in the circuit A of a power converter for converting a DC link voltage into an AC. A current balanced reactor 21 is connected between the switches A and B to balance the circuits A and B to equally share currents of both the circuits A and B, and phase differences or time differences of control signals of corresponding semiconductor switching elements 1, 2, 3, 4, 11, 12, 13, 14 of the circuits are applied including zero. Thus, since output voltage waveforms of the circuits can be controlled more finely, the degree of freedoms at the time of forming waveforms is large, and an output high frequency can be largely reduced.