A dual liquid crystal display (LCD) device including a first LCD panel displaying an image on a first surface; a second LCD panel formed on the same substrate to display an image on a second surface; a light source disposed at an adjacent side under the first LCD panel; a light guide disposed under the first and second LCD panels and including a first light guide block corresponding to the first LCD panel and having dot patterns formed in a first surface and a second light guide block corresponding to the second LCD panel and having taper-cascade grooves formed on a first surface; and a housing settling the first and second LCD panels, the light source and the light guide and having an opening to correspond to an image display surface of the second LCD panel.