In a liquid crystal display device, a recessed portion is formed in a portion of a periphery of a lower frame, a columnar member is provided to the recessed portion, the columnar member is allowed to pass through a hole formed in a projecting portion which is provided on an optical sheet, and a side surface of a liquid crystal panel is brought into contact with the columnar member. The columnar member provided on the lower frame not only determines the position of the liquid crystal panel with respect to the lower frame, but also determines the position of the optical sheet with respect to the lower frame and firmly holds the optical sheet onto the lower frame, thus preventing the disengagement of the optical sheet from the lower frame.