An object is to eliminate fixed pattern noise due to unevenness or variation of the threshold voltages in DA converters and buffer circuits, when forming a pixel portion integrated with a peripheral driver circuit, including the DA converters, by using polycrystalline Si TFT. For that purpose, a pixel common electrodes is provided independently for each of a signal line, and an output of the buffer circuit is connected to both the common electrode and the signal electrode through a switch. With this, the variation of the threshold voltages in the buffer circuits are cancelled between the common electrode and the signal electrode, thereby enabling to remove the above-mentioned fixed pattern noise therefrom.