A light curing device used to solidify resin with a particular wavelength of beam comprising a shell, a heat sink, a light curing device and an air guide unit. The shell has an air inlet at the extremity and several air outlets around the side wall thereof. The heat sink is inside the shell. The light source device which is disposed inside the shell and at another extremity has at last one light unit closed the heat sink. The air guide unit is disposed inside the air inlet. The light curing device adapts an improved cooling structure to increase cooling efficiency, reduce the noise and vibration, and reduce unit weight.