A pixel is provided in which normal display of an image is possible even if a sustain period is shorter than an address period in a driving method combining digital gray scales and time gray scales, and in which operation can be compensated by changing the electric potential of a signal line even for a case in which the EL driver transistor becomes normally on due to deterioration. One of a source region and a drain region of an erasure TFT is connected to an electric current supply line, and the remaining one of the source region and the drain region is connected to a gate signal line. It is possible to change the voltage between a gate and a source of an EL driver TFT by changing the electric potential of the gate signal line so that the EL driver TFT is placed in a non-conducting state with certainty with this structure, even for cases in which the EL driver TFT becomes normally on due to a shift in the value of its threshold voltage.