According to an aspect, a display device includes: an image display panel; a color conversion device including a signal processing unit and a signal output unit; a planar light-source device; and a light-source-device control unit. The signal processing unit includes a color conversion circuit that converts an input signal in a reference color area into a converted input signal generated in a definition color area where a chromaticity point of at least one of a first color, a second color, and a third color is inside of a reference color area, and a four-color generation circuit that generates an output signal and a light-source-device control signal from the converted input signal. The signal output unit outputs the drive signal to each sub-pixel based on the output signal. The light-source-device control unit outputs a drive voltage for emitting white light on the planar light-source device based on the light-source-device control signal.