A liquid crystal display device that displays an image by inputting n (n is a natural number) bit digital signals has n memory circuits in each pixel. The n memory circuits store n bit digital signals, which are converted into corresponding analog signals by a D/A converter provided in each pixel so that the analog signals are inputted to a liquid crystal element. Therefore, when a still image is to be displayed, the stored digital signals are repeatedly used once the digital signals are written in the memory circuits. During the still image is displayed, a source signal line driving circuit and other circuits can stop their driving. Power consumption of the liquid crystal display device thus can be reduced.