A heat dissipation device includes a base, a first heat sink mounted over the base and connected to the base via two first heat pipes, and a second heat sink located at a lateral side of the first heat sink and thermally connected to the base via a second heat pipe. The first heat sink includes two fin groups. One of the fin groups is stacked on the other fin group. Each of the fin groups includes a plurality of fins spreading radially from a center of the fin group to a periphery of the fin group along horizontal directions.