A proposed backlight is suitable for a large size liquid crystal display. A backlight 2 for illuminating a liquid crystal panel 3 from the rear, is formed by combining a plurality of backlight units 10, 10, . . . . By providing a transparent acrylic board 4 between the backlight 2 and the liquid crystal panel 3, it becomes possible to prevent brightness unevenness from occurring at a junction section of the backlight units 10, 10, . . . , even when the backlight is formed by combining the plurality of the backlight units 10, 10, . . . .