A power module includes a heat radiation layer having the first main
surface and the second main surface of reverse side opposed to the first
main surface, an insulation layer disposed on the first main surface of a
radiation layer, a wiring portion of current circuit disposed on the
insulation layer and a plurality of switching elements disposed on the
insulation layer and electrically connected to the wiring portion of
current circuit. A plurality of external terminals are electrically
connected to the wiring portions of current circuit. Furthermore, the
module has a resin sealing all of the insulation layer, a wiring portion
for current circuit, switching elements and the first main surface of the
radiation layer, and a resin sealing a portion of the second main surface
of the radiation layer with the resin.