A heat dissipation device includes a heat dissipation body and a heat conducting body thermally combined with the heat dissipation device. The heat dissipation body includes a central portion defining a through hole therein and a plurality of fin extending from a periphery of the central portion. Each of the fins branches a plurality of portions at an end thereof. The heat conducting body includes a column thermally fitted in the through hole of the central portion of the heat dissipation body. A cavity is defined between the column and the central portion of the heat dissipation body. The cavity contains a phase-changeable medium therein, which becomes vapor once the column absorbs heat from a heat-generating electronic device.