A power semiconductor module includes a base plate as a metallic heat dissipating body, a first insulating layer on the base plate, and a first wiring pattern on the first insulating layer. On a predetermined region that is a part of the first wiring pattern, a second wiring pattern for a second layer is laminated via only a second insulating layer made of resin, thereby forming a pattern laminated region. A power semiconductor element is mounted in a region other than the pattern laminated region on the first wiring pattern. The base plate, the first insulating layer, the first wiring pattern, the second insulating layer, the second wiring pattern, and the power semiconductor element are integrally sealed with a transfer mold resin, thus obtaining the power semiconductor module.