PURPOSE: A light guide device is provided to remarkably eliminate a dark spot of a corner of a backlight by uniformly forming the distribution of light ray inside a light guide plate. CONSTITUTION: A light guide plate(403) irradiates light through a upper side. A light emitting face is contiguous to the optical film set(407). An optical guiding stick(404) is arranged in both sides of the light guide plate. The cross section approaching to the light source of the optical guiding stick is a light incidence surface(410). The side contacting the light guide plate is a light radiating face of the optical guiding stick. The face facing the light radiating face is an optical reflective surface of the optical guiding stick.
