To allow small and light semiconductors to be produced while compris ing an appropriate heat radiation effect at low cost, by forming a heat generat ing semiconductor element attaching plate and a heat radiation part separately, and then putting them together.

A heat generating semiconductor element attaching plate 2 and a heat radiation part 3 are separately formed, then they are put together for forming a heat radiator 1. The heat radiator 1 comprises, for example, the heat generating semiconductor element attaching plate 2 and the heat radiation plate 3, and the heat radiation plate 3 comprises plural thin plate materials 4 for suppressing the temperature rise at a semiconductor element 5. The semiconductor element attaching plate 2 and the thin plate material 4 are put together by calking. The heat radiation plate 3 is formed by using plural thin plate materials 4 formed into a U-shape in cross section, and surface-contacted to the semiconductor element attaching plate 2. To such heat radiator 1 as this, the semiconductor element 5 is attached with a heat generating element attaching vis 6. Further, a heat radiator attaching terminal 7 is provided at both ends of lower part of the heat radiation part.