To provide a power semiconductor device having a nut for attaching external wiring for power that is capable of preventing problems such as the deformation of a main electrode terminal, nut dropout or the like.

The power semiconductor device has the main surface of a case, a resin case formed of resin, and a nut. The nut has a main body that longitudinally extends, and a flange that extends substantially perpendicularly to the longitudinal direction and has a main surface opposing the main surface of the case. In addition, the nut is embedded in the resin case such that the main surface of the flange is supported by the resin. This enables the prevention of the problems such as the deformation of the main electrode terminal, nut dropout or the like.