The heat sink fan for cooling a heat generating device as disclosed in the present invention is provided with a heat sink that is to be directly mounted on the heat generating device to thereby absorb or disperse the heat generated by the heat generating device, and a housing that is detachably engaged to the heat sink and equipped with a fan, which in turn creates air flow to forcibly cool the heat sink. The housing has a top wall portion and a pair of side wall portions extending vertically downwardly from both sides of this top wall portion, the side wall portions being disposed at both sides of the heat sink and provided with an engaging element at which tip an engaging projection is formed. The housing may be detachably coupled with the heat sink the engaging projection being permitted to engage a retaining means formed on a circuit board on which the heat sink or the heat generating device is mounted.