A semiconductor device includes: a first lead; a first semiconductor element mounted on the first lead; and a sealing resin that covers the first semiconductor element, wherein the first lead includes: a first die pad having a first main surface and a first back surface facing opposite sides to each other in a thickness direction; a second die pad arranged side by side with the first die pad in a first direction orthogonal to the thickness direction, and located on a side of the first main surface with respect to the first die pad in the thickness direction; and a connecting portion connected to the first die pad and the second die pad, and wherein the first back surface is exposed from the sealing resin.