PURPOSE: To realize accurate color expression, and prevent the confusion of an observer, by corresponding with the change of a forward direction voltage due to the environmental temperature of an LED which emits one color in a picture element, and controlling the current of an LED which emits the other color.

CONSTITUTION: A voltage measuring circuit 26 is connected between the anode and the cathode of a green color LED 4G (or a blue color LED 4B), measures the forward direction voltage, and operates the correction value. The output of the voltage measuring circuit 26 is inputted in a programable constant current circuit 25. By the correction value on the basis of the forward direction voltage of the green color LED 4G, the value of a current applied to the red color LED 4R is controlled so as to obtain adequate brightness. For example, when a picture element 311 is selected by a driver circuit 21, the forward direction voltage of an LED 4G11 which emits light as the result of the selection is measured, and the luminance for a red LED 4R11 is corrected.