A backlight unit and a liquid crystal display device are provided. The backlight unit includes light emitting diodes; and a plurality of temperature adjusting members which reduce a temperature difference formed by emission of heat of the backlight unit, the heat being caused by a convection current of air in a vicinity of the light emitting diodes and by heat emitted from the plurality of light emitting diodes. The liquid crystal display device includes a plurality of circuit boards which are provided with light emitting diodes; a frame on which the circuit boards are installed; and a plurality of temperature adjusting members provided between the plurality of circuit boards and the frame, wherein the plurality of temperature adjusting members having different heat resistances are arranged according to a temperature distribution of heat emitted from the light emitting diodes such that a uniform temperature distribution is maintained across the display device.