A backlight unit for a liquid crystal device capable of obtaining a high-quality image and reduced in thinness. The backlight unit is disposed below a liquid crystal panel to irradiate light thereoto. A plurality of separate light guide plates define respective blocks. Groups of LEDs each are disposed along an edge of each of the light guiding plates, each of the LED groups emitting light toward a corresponding one of the light guide plates. The each LED group is turned on and off according to the corresponding block.