The display driver includes: a display data compression circuit; a recording circuit; a display data decompression circuit; and an output circuit. Further, the display driver is provided with a compressibility setting circuit. The display data compression circuit has the function of compressing the display data according to a compressibility set by the compressibility setting circuit. With the display driver arranged like this, the power consumption can be reduced by increasing the compressibility for a displayed image such that the image quality is not noticeably deteriorated even with the compressibility increased. Further, for the displayed image such that the image quality is noticeably deteriorated with the compressibility increased, a sufficient image quality after data decompression can be secured by lowering the compressibility.