According to an aspect, a display device includes: an image display panel; a signal processing unit; and a signal processing circuit. The signal processing unit calculates an extension coefficient α for an input signal, calculates an output signal of a first sub-pixel, calculates an output signal of a second sub-pixel, calculates an output signal of a third sub-pixel, calculates an output signal of a fourth sub-pixel, and calculates a control signal. The signal processing circuit performs filtering processing on the control signal by a set first time constant to calculate and output a light-source device control signal, when the control signal is smaller than a set threshold value, and performs filtering processing on the control signal by a set second time constant to calculate and output the light-source device control signal, when the control signal is equal to or larger than the threshold value.