A light emitting device capable of suppressing generation of pseudo-contours by increasing the frame frequency while suppressing the drive frequency of a driver circuit is provided. According to the present invention, gray scales are displayed not only by controlling the emission period of a light emitting element, but also by controlling the luminance of the light emitting element. Specifically, one frame period is divided into a plurality of sub-frame periods each having an equal length, and the luminance of the light emitting element in each sub-frame period is controlled to have different levels. By controlling the total sum of the luminance level of the sub-frame periods that are selected with a video signal, a desired gray scale can be displayed.