The method of fine gradation display by an electro-optical device with little influence by difference in elemental devices, is disclosed, which is an object of the present invention. In case of an active matrix electro-optical device, a visual gradation display can be carried out by digitizing an analog image signal externally supplied by means of binary notation, by temporarily storing the digital signal thus obtained, by outputting the digital signal to a circuit of next step in a proper order, and by controlling the output timing of the signal so as to output the signal to the active matrix electro-optical device, and whereby digitally controlling the time for applying voltage to a picture element.