To provide a heat sink where heat dissipation capacity and thermal fatigue characteristics are good and the bonding strength of solder bonding is high and a plating cost is low.

An aluminum fin 1 processed into the shape of an accordion and a copper plate 2 are solder bonded to each other and copper plating of 1.0-20 μm in thickness or plating containing nickel of 0.5-20 μm in thickness is applied to the solder bonded surface of the aluminum fin 1. Alternatively, the aluminum fin and an aluminum plate are solder bonded to each other and copper plating of 1.0-20 μm in thickness or plating containing nickel of 0.5-20 μm in thickness is applied to the solder bonded surfaces of the aluminum fin and the aluminum plate.