An LSI cooling apparatus having various structures is used in electronic devices such as computer systems. In particular, the LSI cooling of apparatus is suitable for cooling of LSIs having high heat generating densities. In a cooling apparatus of the present invention, a heat sink is constructed to be small in pressure loss and excellent in cooling performance. This is because the heat sink comprises thin wire fins so set that the Reynold's number may not exceed 40. As a result, LSIs generating a large amount of heat can be cooled. Further, a heat sink having rigidity can be obtained by disposing wide-width wire drawn substances in thin wires or by using supports. Further, a computer comprising LSIs equipped with heat sinks can cope with various cooling air sending methods and it can be cooled with low noises.