A liquid crystal display device characterized by comprising a main body case (3) having opposed side walls (31, 31) and other portions (32, 32) opened and a relatively wide U-shaped bottom wall (30), a backlight unit (4) received in the main body case (3), and an optical member (1) placed on the surfaces of both side walls (31, 31) of the main body case (3) while covering the backlight unit (4), wherein the optical member (1) is placed on the surfaces of both side walls (31, 31) of the main body case (3) in which the backlight unit (4) is received, and is fixed by picture- frame-like reinforcing frames (6, 7) whose outer periphery is joined at the corners.