A semiconductor device includes a semiconductor chip having a first main surface and a second main surface; a stacked structure on which the semiconductor chip is disposed; and a cooling body on which the stacked structure is disposed. The stacked structure includes a first thermal conductor fixed to the cooling body, an insulator disposed on the first thermal conductor, and a second thermal conductor disposed on the insulator and having the semiconductor chip disposed thereon. The first main surface of the semiconductor chip opposite to the second main surface in contact with the stacked structure is sealed with an insulation material. At least a part of the first thermal conductor protrudes outwardly of the insulation material in plan view.