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 (51). The liquid crystal display device includes a plurality of circuit boards (52) which are provided with light emitting diodes; a frame on which the circuit boards are installed; and a plurality of temperature adjusting members (53) 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.