A heat dissipating module of an electronic device includes a casing, a circuit board, at least one heat generation element, and a fastening assembly. The casing includes at least one lateral plate. The at least one heat generation element is firmly fixed on the at least one lateral plate through a fixing element. After the at least one lateral plate and the circuit board are combined together through the fastening assembly, the at least one lateral plate and the circuit board pass through a reflow furnace, so that the at least one heat generation element is welded on the circuit board. The heat generated by the at least one heat generation element is transferred to the at least one lateral plate of the casing so as to be dissipated away.