To provide a light emitting device without nonuniformity of luminance, a correcting circuit for correcting a video signal supplied to each pixel to a light emitting device. The correcting circuit is stored with data of a dispersion of a characteristic of a driving TFT among pixels and data of a change over time of luminance of a light emitting element. Further, by correcting a video signal inputted to the light emitting device in conformity with a characteristic of the driving TFT of each pixel and a degree of a deterioration of the light emitting element based on the over-described two data, nonuniformity of luminance caused by a deterioration of an electroluminescent layer and nonuniformity of luminance caused by dispersion of a characteristic of the driving TFT are restrained.