A control circuit changes the ratio of an illumination period to a non-illumination period in a frame period of a backlight according to a gradation level in the one frame period of an image displayed on a liquid crystal panel in such a manner that the higher the gradation level, the backlight illumination control circuit increases the ratio of the illumination period to the non-illumination period in the frame period of the backlight, and the lower the gradation level, the backlight illumination control circuit decreases the ratio of the illumination period to the non-illumination period in the frame period of the backlight and thereby controls illumination intensity toward the liquid crystal panel. A time center of illumination intensity in each one frame period of the backlight is controlled in order that the time center exists in a constant temporal position from the beginning of each frame period.