PURPOSE: To easily manufacture radiating fins which are continuously formed by bending leg parts, side parts and top parts having radiating holes and improve radiating effect and have no fear of vibration to the individual piece.

CONSTITUTION: To a part 2 for forming the leg part and a part 3 to form the side part in a flat platre 1, base material fitting holes 4 are bored, and a part 5 for forming the top part in the flat plate 1, the radiating holes 6 are bored. The flat plate 1 completing borings, is bent at the positions of chain lines in the figure to form the radiating fin 10 continuing each of the leg part 7, side part 8 and the top part 9. The radiating fin 10 is fitted to the base material having protruded stripe which can be fitted to the base material fitting holes 4. Further, the boring of radiating holes 6 can be executed after bending the flat plate 1 or after fitting to the base material by using laser beam boring or the other boring means.