A heat dissipation device includes a heat conducting core having a heat receiver and a column extending from the heat receiver. A first fin unit includes a plurality of first fins radially extending from the core. The first fins curve along an anticlockwise direction. A plurality of first passages is defined between the first fins. A second fin unit includes a plurality of second fins radially extending from the core. The second fins curve along a clockwise direction. A plurality of second passages is defined between the second fins and communicating with the first passages of the first fin unit. A fan is positioned on the second fin unit for providing forced airflow to the second passages of the second fin unit and then the first passages of the first fin unit. The fan rotates anticlockwise.
