To provide a circuit which inhibits shift of a threshold voltage of a gate electrode of a transistor which is easy to deteriorate and shift of a threshold voltage of a turned-on transistor, and provide a driving method of the circuit in a display device having a circuit which includes transistors, especially, a display device which uses as a display medium an electro-optical element such as a liquid crystal or a light-emitting element.

In a semiconductor device, shift of a threshold voltage of a transistor which is easy to deteriorate and shift of a threshold voltage of a turned-on transistor are inhibited by inputting a signal to a gate electrode of the transistor which is easy to deteriorate through the turned-on transistor. The semiconductor device includes a constitution in which AC pulses are applied to the gate electrode of the transistor which is easy to deteriorate through a transistor with a gate electrode to which high potential (VDD) is applied (or through an element having a resistant component).