Abstract: A nail lamp device includes an inner housing having an inner housing substrate and an inner chamber surrounded by the inner housing substrate, at least one chip on board (COB) light emitting diode (LED) module disposed on an inner surface of the inner housing substrate by pasting-fitted and emitting light toward the inner chamber, a control module disposed on an outer surface of the inner housing substrate and electrically connected to the COB LED module, and an outer housing covering the inner housing and retaining a front opening of the inner chamber exposed. The COB LED module used by the nail lamp device is directly disposed on the inner surface of the inner housing substrate by pasting-fitted and has a plurality of LED elements arranged in array to accelerate the time required for the curing reaction of the resin coatings or glues coated on fingers. Moreover, the wavelength ranges of light can be selected with high elasticity, so as to enhance utility.