An erasing device for a liquid crystal display image of the present invention is furnished with an auxiliary power source for continuously supplying power source to a liquid crystal display panel for a certain period after the main power source of the main body of the liquid crystal display device is turned OFF. Upon input of a power source OFF signal directing to turn OFF the main power source, a driving signal generating circuit and a driver controller light up the liquid crystal display panel entirely on a saturation voltage of the liquid crystal and subsequently shut off the same entirely using the power supply from the auxiliary power source. Consequently, it has become possible to erase an afterimage quickly on an active matrix liquid crystal display panel with a memory maintaining function of a liquid crystal display device, thereby not only upgrading the display quality, but also preventing deterioration of the liquid crystal caused by an application of an abnormal voltage associated with the occurrence of an afterimage.