A heat dissipation device is described. The heat dissipation device is suitable for electrical equipment, and particularly for a notebook computer. The heat dissipation device has a cooling fan and a plurality of heat dissipation fins. The heat dissipation fins are disposed at an outlet of the cooling fan to exhaust heat on the heat dissipation fins with airflow generated by the cooling fan. Each of spaces between the adjacent heat dissipation fins is determined so as to make the airflow velocity uniform. A preferred predetermined space is about C.sub.1.times.1/(V.sup.2-1), where V is an original airflow velocity at the adjacent heat dissipation fins and C.sub.1 is a coefficient.