An insulation film that strongly adheres to a power semiconductor module having a resin sealer and a conductor plate and has high thermal conductivity is provided.An insulation layer 700 is provided between a power semiconductor module 302 and a heat dissipation portion 307B. The power semiconductor module 302 includes a resin sealer 348, which covers a circumferential side surface of a conductor plate 315, and a plurality of recesses 348D are provided in the resin sealer 348. The insulation layer 700 is formed of a spray coated film 710, an insulation film 720, and a resin layer 730, and the spray coated film 710 is formed on the surface of the resin sealer 348 including recesses 348D to form a seamless flat surface. The planar size of each of the recesses 348D is greater than the planar size of each flat portion 711, which forms the spray coated film 710.