The cooling apparatus has cooling fins attached to heat generating units of electronic devices and provided with a plurality of elemental fins. According to one embodiment, the cooling apparatus has a first cooling fin composed of elemental fins that are uniform in fin density in the height direction of the cooling fin from a fin base. The cooling apparatus also has a second cooling fin composed of elemental fins with a zero or small fin density at the lower portion close to a fin base of the cooling fin as compared with the fin density at the upper portion of the cooling fin. The first and second cooling fins are positioned adjacent to one another. Various different embodiments of cooling fins are disclosed.