A backlight unit includes a DC-DC converter; a voltage control unit which controls output voltage of the DC-DC converter; a plurality of unit light emitting diode arrays; and current deviation compensating unit in connection with input terminals of the plurality of unit light emitting diode arrays. The current deviation compensating unit receives the controlled voltage of the voltage control unit and transfers a feedback signal to the voltage control unit based on the received voltage, and actively compensates a current deviation generated by electrical characteristics of the plurality of unit light emitting diode arrays and transfers the compensated current deviation to the input terminals of the plurality of unit light emitting diode arrays.