A liquid crystal display device has a liquid crystal display panel and a backlight. The backlight includes plural line light sources arranged in parallel with each other, a transparent optical plate disposed on a liquid-crystal-display-panel side of the line light sources, plural minute optical controlling elements formed on a liquid-crystal-display-panel-side surface of the transparent optical plate. The plural minute optical controlling elements extend in parallel with the line light sources, and are symmetrical in a cross section perpendicular to longitudinal axes of the plural line sources, between two adjacent midplanes each of which passes midway between two adjacent ones of the plural line light sources and each of which is perpendicular to the transparent optical plate.