There is provided a heat-emitting element cooling apparatus capable of enhancing cooling effect on a heat-emitting element as well as reducing noise. A heat sink includes a core portion and a plurality of radiation fins fixed to the core portion. Dimensions of the core portion and the radiation fins are defined in such a manner that the diameter L1 of the core portion should be 37% to 45% of the diameter L2 of a shape depicted by a virtual connecting line which connects end portions of the radiation fins.