A heat dissipating device includes a fin unit disposed on a supporting
seat, and an anchoring frame disposed on the fin unit and engaging
detachably the supporting seat for anchoring the fin unit between the
supporting seat and the anchoring frame. A fan module includes a fan unit
having a fan blade disposed in a fan housing that is mounted on the fin
unit, a connecting seat mounted on the fan housing and formed with a
through hole that is in fluid communication with an inlet hole in the fan
housing, and an air guiding member mounted on the connecting seat and
confining an air passage that is in fluid communication with the through
hole in the connecting seat. The fan unit is operable so as to draw
external air toward the fin unit via the air passage.