A semiconductor device of the present invention includes: a first substrate (1) on which a power semiconductor element (2) is mounted; a heat-dissipating plate (12); an insulating layer (11) disposed between the first substrate (1) and the heat-dissipating plate (12); and molding resin (4) that molds the first substrate (1), the heat-dissipating plate (12), and the insulating layer (11). The heat-dissipating plate (12) has a first surface opposite to the insulating layer (12), the first surface being exposed from the molding resin (4). The insulating layer (11) has a curved area (11a) that is curved to the first surface and an end that is located in the molding resin (4).