A heat dissipation device includes a heat sink (10) and at least a serpent heat pipe (22). The heat sink (10) comprises a base (12) contacting with an electrical component, a heat dissipation fins group (14) secured to the base (12) and a cover (16) attached to a top of the heat dissipation fins group (14). The heat dissipating fins group (14) defines a notch (148) at one side thereof. Two end portions of the heat pipe (22) are respectively connected to the base (12) and the cover (16), and a middle portion of the heat pipe (22) is accommodated in the notch (148).