The laser device includes a substrate, a laser element disposed on the substrate for emitting a laser light ray, a light guide member disposed on the substrate, and a wavelength conversion layer. The light guide member is light-transmissible and thermally conductive, and has at least one reflection surface for reflecting the laser light ray from the laser element so as to change travelling direction of the laser light ray. The wavelength conversion layer converts wavelength of the laser light ray from the light guide member to result in a laser beam, and contacts the light guide member so that heat from the wavelength conversion layer is transferred to the substrate through the light guide member.