A light emitting device capable of suppressing drop in luminance or luminance unevenness of a light emitting element due to deterioration of an electro luminescent material and capable of switching an image direction vertically to horizontally without a frame memory additionally provided. The light emitting device of the invention comprises in each pixel first to fourth transistors, a light emitting element, and a signal line. The first transistor and the second transistor control the connection between the signal line and a gate of the third transistor, the fourth transistor controls a current value supplied to the light emitting element, and the third transistor selects whether the current is supplied to the light emitting element or not. Further, the first transistor and the second transistor are switched separately.