The cold cathode tube for illuminating pixels with light which is in accordance with an output signal has luminance which gradually increases at a rise and gradually decreases at a fall per one frame time. The cold cathode tube contains a fluorescent material of only one of three primary colors of light, and has a certain OFF period or dimming period per one frame time. Between a diffusing plate and a reflecting plate are provided partition walls for parting emitting areas, so that the illumination light of one cold cathode tube does not reach the display elements to be illuminated by the other cold cathode tubes. The emission of each display element is changed per one frame time between a normal ON state and a dim state. The cold cathode tube has two or more OFF periods within one frame time, and, luminance of the cold cathode tube is changed per one frame period. As a result, it is possible to suppress shortening of life of emitters in an illuminating section, and to relieve lowering of luminance of the emitters, and also to obtain a desirable display quality even in a fast-moving image.