Display irregularities in light emitting devices, which develop due to dispersions per pixel in the threshold value of TFTs for supplying electric current to light emitting elements, are obstacles to increasing the image quality of the light emitting devices. An electric potential in which the threshold voltage of a TFT (105) is either added to or subtracted from the electric potential of a reset signal line (110) is stored in capacitor means (108). A voltage, in which the corresponding threshold voltage is added to an image signal, is applied to a gate electrode of a TFT (106). TFTs within a pixel are disposed adjacently, and dispersion in the characteristics of the TFTs does not easily develop. The threshold value of the TFT (105) is thus cancelled, even if the threshold values of the TFTs (106) differ per pixel, and a predetermined drain current can be supplied to an EL element (109).