An object is to provide a technique in which a cost reduction in a power semiconductor device can be achieved while maintaining heat dissipation performance as much as possible. A power semiconductor device includes a leadframe, a power semiconductor element disposed on an upper surface of the leadframe, and an insulating layer disposed on a lower surface of the leadframe. At least a partial line of a peripheral line of a region where the insulating layer is disposed, on the lower surface, is aligned, in top view, with at least a partial line of an expanded peripheral line obtained by shifting outwardly, by the amount corresponding to the thickness of the leadframe, the peripheral line of the region where the power semiconductor element is disposed, on the upper surface.