There is provided a liquid crystal display device using a light guide plate dividing method that clearly establishes a structure for fixing divided light guide plates. An LED backlight unit according to an aspect of the invention may include: a lower cover having a mounting hole therein; a board provided on the lower cover and having a through hole facing the mounting hole of the lower cover; a plurality of LED packages mounted onto the board and supplying light; a light guide plate provided on the lower cover and guiding light supplied from the LED packages; and a fixation unit inserted into the mounting hole and the through hole so that the light guide plate is pressed against the lower cover.