Heat sink for cooling a heat producing element and application

The heat sink has a heat sink body (1) made of a good heat conductive material and a fan assembly (2) installed inside the heat sink body. The heat sink body is efficiently air-cooled by a cooling air generated by the rotation of the fan assembly. The cooling air forcibly cools a base and a fixing wall of the base adjacent to the heat producing element and plate-like radiating fins or a pin-like radiating fins are protruded on the heat sink body to radiate the heat effectively. The position of the fan assembly is as the center of the heat sink body or is at the offset position from the center of the heat sink body. The heat sink of the present invention can be installed in a portable electronic apparatus such as a portable computer.