A semiconductor device includes a lead, a first semiconductor element, and a sealing resin that covers at least a portion of each of the lead and the first semiconductor element. The lead has an obverse surface on which the first semiconductor element is mounted, and a reverse surface opposite to the obverse surface. The lead includes a first portion having a first surface. The first surface is located between the obverse surface and the reverse surface in the z direction in which the obverse surface and the reverse surface are separated from each other. The first surface of the lead is covered with the sealing resin, and is configured with a plurality of protruding areas and a plurality of recessed areas arranged alternately as viewed in the z direction.