One frame is divided into three sub-frames of red, green and blue colors, and, in each sub-frame, the time (TA) necessary for writing scanning, the time (TC) necessary for erasing scanning, the time (TB) from the end timing of writing scanning to the start timing of erasing scanning, and the time (TD) from the end timing of erasing scanning to the start timing of writing scanning of the next color (the next sub-frame) are each 25% of the sub-frame. The relations TB+TC=TA+TD, and TB=TD are satisfied. A back-light is turned on during the time from the start timing of writing scanning to the end timing of erasing scanning, and is turned off during the time from the end timing of erasing scanning to the start timing of writing scanning of the next color. The ON time of the back-light is 75% of the sub-frame.