A display device includes: an image display panel including a plurality of pixels each including first to fourth sub-pixels; and a signal processing unit. The signal processing unit determines an expansion coefficient related to the image display panel, obtains output signals of the first to the third sub-pixels based on at least input signals of the first to the third sub-pixels and the expansion coefficient to be output to the first to the third sub-pixels respectively, obtains a fourth sub-pixel correction value as a correction value of an output signal of the fourth sub-pixel based on the input signals of the first to the third sub-pixels and the expansion coefficient, and obtains the output signal of the fourth sub-pixel based on the input signals of the first to third sub-pixels, the expansion coefficient, and the fourth sub-pixel correction value to be output to the fourth sub-pixel.