A heat sink includes a base, a set of fins and at least an elastic fixing member mounted on a surface of the base. The elastic fixing member includes an elastic sheet mounted on the base, a supporting portion disposed on the elastic sheet and a fixing portion disposed on the supporting portion. The heat sink is secured to a printed circuit board through the fixing portion of the elastic fixing member, with the base of the heat sink being in direct contact with a heat generating component mounted on the printed circuit board. The distance between the base of the heat sink and the heat generating component can be controlled so as to even pressure on the heat generating component and efficiently decrease heat stress.