An LED backlight unit is provided to reduce costs by transmitting a plurality of control signals in a serial interface type. An LED array is arranged on the first surface of a case. A control board(11) is installed at the first side of the second surface of the case. The first LED driver(13) is installed at the second side of the second surface of the case. The second LED driver(15) is installed at the third side of the second surface of the case. The first serial bus line(17) is electrically connected between the control board and the first LED driver. The first serial bus line transmits a plurality of control signals in a serial interface method. The second serial bus line(19) is electrically connected between the control board and the second LED driver.
