PURPOSE: To form an image with high density at a high speed by using ferrodielectric liquid crystal, applying a selective signal between a common and a signal electrode and opening and closing an optical path, and controlling the temperature of the liquid crystal through a heating or cooling means.

CONSTITUTION: Electrodes 311 and 312 provided in a cell are applied with a selective signal by a liquid-crystal driving circuit 310 to control the orientation state of the ferrodielectric liquid crystal 310, and it is detected by polarizers 313 and 314 arranged at both sides. Heating resistors 302 and 303 and a power source 304 are provided as a temperature rising means for bringing a liquid- crystal material 301 under the temperature control of SmC* or SmH*. In many cases, the stable temperature range of SmC* in case of a temperature fall is wider, so the liquid crystal is heated up to an upper limit T2 temporarily, cooled gradually, and held at final temperature T. This control is carried out through a heat sensing element 305 by using heating resistors 302 and 303 stepwise.