Abstract: A power module package includes a power circuit element, a control circuit element, a lead frame, an aluminum oxide substrate having a heat sink and an insulation layer, and a sealing resin. The control circuit element is electrically connected with the power circuit element to control chips within the power circuit element. The lead frame has external connection terminal leads in its edge and has a first surface to which the power circuit element and the control circuit element are attached and a second surface which is used as a heat transmission path. The heat sink is a plate made of metal such as aluminum and the electrical insulation layer is formed at least on an upper surface of the heat sink and made of aluminum oxide. The electrical insulation layer may be formed over an entire surface of the heat sink. Here, the insulation layer is attached to the second surface by an adhesive, on a region below where the power circuit element is attached, to the first surface of the lead frame.