PURPOSE: To lower cost for temperature control in using by equipping a semiconductor integrated circuit part of a large power consumption with a radiation metallic plate one surface of which is exposed from the part sealing part and which can be connected to an electronic circuit board to mount the part thereon.

CONSTITUTION: A radiation metallic plate 1 made of a highly heat conductive material such as copper is installed to a semiconductor integrated circuit part 2 of a large watt consumption, the island part 5 of a lead frame is mounted on the radiation metallic plate 1 and adhered thereto with solder or heat conductive bond, and they are sealed with a mold 7 so that one surface of the radiation metallic plate 1 may be exposed to an air. The lead parts 4 of the lead frame and the exposed part of the radiation metallic plate 1 are connected to an electronic circuit board 6 with solder. Forming this structure enables increasing the quantity of radiated heat and lowering costs for suppressing the rise of the temperature of the part in using.