A light-guide plate (LGP) includes a light-incident surface, a light-facing surface, a light-emitting surface and a light-reflecting surface. The light-incident surface receives light. The light-facing surface has a smaller size than that of the light-incident surface. The light-facing surface faces the light-incident surface. The light-emitting surface is extended substantially perpendicular to the upper side of the light-incident surface. The light-emitting surface is connected to the upper edge of the light-facing surface. The light-reflecting surface has a plurality of first prism patterns that are formed parallel with the light-incident surface. The light-reflecting surface is extended from the base of the light-incident surface to be connected to the base of the light-facing surface. Therefore, a leakage of light that exits from the wedge-type LGP through a side surface of the wedge-type LGP is decreased, so that luminance is enhanced.