PURPOSE: To provide a heat radiator which generates no galvanic corrosion even when an aluminum radiator and a copper external conductor are connected.

CONSTITUTION: By the formation of a copper layer 10 on the external conductor mounting terminal part 4 of an aluminum heat radiating body 1, electrolytic corrosion can be prevented because a copper external connecting conductor is brought into contact with the copper layer 10. Also, as the mounting structure of the aluminum heat discharging body is constructed in such a manner that a flat washer 11, having one surface formed by aluminum material 12 and other surface formed by copper material 11, is interposed, the contact surface with the external connecting body 7 and the contact surface with the external conductor mounting terminal part have the metal of the same quality. As a result, electrolytic corrosion can be prevented.