Provided is a liquid crystal display device that can reduce costs while preventing moving image blurring. The device includes a liquid crystal panel and a backlight device. The backlight device includes a rectangular light guide plate 10 in plan view, and a light source unit emitting light toward a light incident surface corresponding to a side surface of the light guide plate. The light source unit is configured by a plurality of light source blocks arranged in a Y direction. The light guide plate 10 includes a groove structure 32 for taking out light upward on its front surface opposed to a back surface of the liquid crystal panel, and a dot pattern 31 for scattering light on its back surface. The groove structure 32 has a plurality of stripe-like grooves extending in an X direction, wherein a ridge extending in the X direction is formed at a portion sandwiched between the two adjacent grooves.