A backlight unit and a liquid crystal display device improve uniformity of a luminance and a color of a display surface. The backlight unit includes a light source device and a circuit board, the light source device including a first board and a plurality of point light sources connected in series, the plurality of point light sources being arranged on the first board, and the circuit board including a second board, a driving circuit for the plurality of point light sources, and a variable resistance device, the driving circuit for the plurality of point light sources and the variable resistance device being arranged on the second board, wherein a resistance adjusting element of the variable resistance device is exposed to an outside, and at least one point light source arranged on an end side among the plurality of point light sources is connected in parallel to the variable resistance device.