A light-emitting diode (LED) lamp device includes at least one light-emitting module and a heat-dissipation module. The heat-dissipation module includes a plurality of cooling fins arranged in a radial pattern and connected annularly at intervals around the light-emitting module. Each of the cooling fins has an outer rim folded back a predetermined distance toward the light-emitting module to form a bent edge. The bent edges are formed with arcuate folded-back portions so that the cooling fins have rib-like outer perimeters after the bent edges are formed. Thus, the LED lamp device is allowed to be held safely by the folded-back portions while the cooling fins are structurally strengthened.