A heat dissipation device includes a base and two heat sinks formed by aluminum extrusion and located on the base. Each heat sink includes a heat conducting portion. The two heat sinks include a plurality of first fins extending inwardly from first faces of the heat conducting portions and located between the heat conducting portions, and a plurality of second fins extending outwardly from second faces of the heat conducting portions. Two heat pipes connect the base and the two heat sinks. Each heat pipe includes a first section thermally engaged with the base, and two second sections extending from the base and thermally engaged with the heat conducting portion of a corresponding heat sink. The second sections are located outside a hub and below fan blades of an impeller of a fan mounted on the heat sinks.