Abstract: The mounting structure of a power device is simplified so as to reduce cost while achieving improvements in heat dissipation and reliability. A power module 100 is comprised of a metal wiring board 13, a power device 11 disposed on an upper surface of the metal wiring board 13 via a solder layer 12, a metal heat dissipating plate 15 disposed on a lower surface of the metal wiring board 13, and a heat sink 19 disposed on a lower surface of the metal heat dissipating plate 15. A resin-based insulating layer 14 is disposed between any desired two of the aforementioned layers.