To output weak voltage/weak current and suppress strain of output voltage/current in a neutral point clamp type electric power transformer device.

This neutral point clamp type electric power transformer device, consisting of: a first, a second, a third and a fourth switching elements connected in series; and a first, a second, a third, a fourth, a fifth and a sixth diodes connected to each of the switching elements in antiparallel, leads out an output terminal from an connection point between the second and the third switching elements, and includes a fifth switching element connected with the fifth diode in parallel, and a sixth switching element with the sixth diode in parallel.