a power semiconductor device m includes : first and second frames for feeding unipolar power from outside ; first and second switching units which are series - connected between the first and second frames ; an output frame for outputting ac power which is generated by conduction and shutoff of each switching unit to outside ; a connecting wire for electrically connecting at least one pair of the first frame and the first switching unit , the first switching unit and the output frame , the output frame and the second switching unit , and the second switching unit and the second frame ; a third frame which is arranged close to the output frame ; and a branching wire for electrically connecting the first switching unit or the second switching unit to the third frame , whereby sufficiently suppressing surge voltage which takes place within the module even using an external snubber circuit .