A heat dissipation device includes a base, a first and second fin sets on the base, and a fan located atop the first and second fin sets. The base has a first face for contacting with an electronic device, and two sloped faces extending from the first face and toward each other. The first fin set defined a channel receiving the base therein. A plat extends from an end of the first face of the base. The second fin set is arranged on the plat of the base. The first face of the base has two grooves defined therein. A retaining member is attached to the first face of the base and has two retaining bars thereof fitted in the two grooves of the first face, respectively.