A light emitting device and an element substrate which are capable of suppressing variations in the luminance intensity of a light emitting element among pixels due to characteristic variations of a driving transistor without suppressing off-current of a switching transistor low and increasing storage capacity of a capacitor. According to the invention, a driving transistor also serves as an erasing transistor and the driving transistor is operated in a saturation region. The gate of the driving transistor is connected to an erasing scan line and it can be selected whether or not to flow current by a potential of the erasing scan line. In addition, a current controlling transistor which operates in a linear region is connected in series to the driving transistor, thus a video signal transmitting a light emission or non-emission of a pixel is input to the gate of the current controlling transistor through a switching transistor.