Abstract: The invention mainly relates to a heat radiator for performing heat radiation of electronic parts (heat generating elements) that are heated by electric supply, such as semiconductor parts to be mounted on a circuit board surface of a printed circuit board. The heat radiator (1) according to the present invention is a heat radiator in which vertical heat radiative portions are formed by bending both right and left ends of a back surface plate (2) to the front face side. The heat generating element (5) that is an electronic part is mounted on the surface on the front face side or the back face side of the back surface plate. The radiating portions are further bent inwardly to form sleeve portions (3) extending up and down. Slits (12a) are formed on outer peripheral walls of the sleeve portions (3) for ventilating air. Inside the right and left sleeve portions (3), the bent back end sides of the peripheral walls of the sleeve portions (3) form bent back portions (4) bent and formed along the back surface plate.