A heat dissipation device includes a heat sink (10) and a blower (50) for generating an airflow to the heat sink. The blower includes a housing (60) and at least one plate (63a, 63b) extending outwardly from the housing. The housing forms a contacting surface (610, 620) abutting a side of the heat sink. The plate includes an inner surface (630) abutting another side of the heat sink. A groove (69) is defined in a junction of the housing and the plate, and thus the contacting surface of the housing and the inner surface of the plate are planar-shaped to avoid interference between the housing of the blower and the heat sink. The groove has chamfer angles R therein. The housing is made by plastic injection molding or die casting.