PURPOSE: To eliminate the unevenness of luminance caused by the contour of a fluorescent tube by putting an EL(electro-luminescence) plate under or between the fluorescent tubes in a direct-under system backlight.

CONSTITUTION: The backlight of a liquid crystal display device is constituted by putting the EL plate 1 under or between the direct-under system fluorescent tubes 3 so that the contour of the fluorescent tube 3 may not appear by the light irradiation of the EL plate 1. Namely, by putting the EL plate 1 wholly under the fluorescent tubes 3, the unevenness of the luminance which has been a trouble in the conventional manner, is eliminated by compensating the shortage of the luminance between the fluorescent tubes 3 by the light irradiation of the EL plate 1. In such a case, the same effect is obtained by providing the EL plate 1 between the fluorescent tubes 3.