A TFT for controlling the amount of current flowing into a power supply line when an EL element does not emit light (electric discharge TFT) is provided in each pixel. When an EL driving TFT is turned ON to make an EL element emit light, the electric discharge TFT is turned OFF. On the other hand, the electric discharge TFT is turned ON when the EL driving TFT is turned OFF and no EL element emit light. Therefore variation of the difference in electric potential over the length of a power supply line depending on an image to be displayed is contained. Thus reduced is the difference in amount of current flowing into EL elements in adjacent pixels while the EL elements emit light, thereby avoiding crosstalk.