A heat dissipation device includes a heat sink having a plurality of fins
defining a plurality of passageways therebetween. The passageways have an
inlet and an outlet at two sides of the heat sink. A fan is located at
the inlet of the passageways of the heat sink for providing airflow to
the heat sink. A guiding member is positioned at the outlet of the
passageways of the heat sink for guiding the airflow to electronic
components around the heat dissipation device. The heat sink defines a
slot at a side thereof, the guiding member extends at least a fixing arm
fixed to the heat sink and a tongue embedded into the slot of the heat
sink, thereby attaching the guiding member to the heat sink.