An analog-to-digital converter converts a video signal into a digital video signal consisting of N bits and outputs the converted signal. A correction value memory stores correction data consisting of M bits which is used to correct the difference in luminance between display pixels on a display. A multiplier multiplies the video signal consisting of N bits output from the analog-to-digital converter by the correction data consisting of M bits stored in the correction value memory, and outputs a video signal consisting of L bits with which the difference in luminance between display pixels on the display is corrected.