A semiconductor device includes a semiconductor module which has an external terminal protruding from one surface thereof; a printed circuit board which is electrically and mechanically connected to the external terminal of the semiconductor module; a heatsink which abuts against the other surface of the semiconductor module opposite to the one surface; and a joint member which serves as an elastic support column having a first head portion and a second head portion. The first head portion is shaped like a truncated cone and disposed at one end of the elastic support column, and the second head portion is disposed at the other end of the elastic support column. The semiconductor module, the printed circuit board and the heat sink are integrated by the first head portions and the second head portions.