A backlight unit, suitable for a large sized LCD device, includes a plurality of fluorescent lamps alternately provided under an LCD panel in at least two parts, formed by dividing a light-emitting surface. Adjacent end parts of the fluorescent lamps are overlapped partially. Each fluorescent lamp is shorter than a length (e.g., horizontal dimension) of the light-emitting surface. A reflective plate is provided below the plurality of fluorescent lamps, and has a rugged part underlying the overlapped portion of the fluorescent lamps. Alternatively or in addition, a light-scattering pattern can be provided in a portion of a light-scattering means, over the overlapped portion of the fluorescent lamps. The rugged part and/or light-scattering pattern prevents obscure rays in the overlapped portion and improves a uniformity of luminance of the backlight unit.