A illuminant keyboard device includes a bottom frame having a plurality of latch parts, a plurality of keying units disposed on the bottom frame, a membrane switch interposed between the bottom frame and the keying units, a light guide plate interposed between the membrane switch and the bottom frame, a least a light source disposed on predetermined position of the light guide plate, a plate interposed between the membrane switch and the light guide plate and a light-shielding plate interposed between the membrane switch and the keying units. The light guide plate has a plurality of first holes and the plate has a plurality of second holes, the diameter of each of the first holes is larger than the diameter of each of the second holes.