PURPOSE: To provide a radiating fin of which thickness and dimension can be arbitrarily set, and a pitch of the radiating fins adjacent to each other can be also arbitrarily set, and assembling thereof is easy.

CONSTITUTION: In a nearly U-shape both side erecting wall 23 composed of a bottom plate 24 and both vertical walls 23, 23, a plurality of inner dowels 25 and outer dowels 26 are respectively formed at different positions, and the apexes of the inner dowels 25 which are formed at opposing positions on both vertical walls 23, 23 are brought into contact with each other.