An object is to provide a semiconductor device that can realize a function of a thyristor without complication of the process. A semiconductor device including a memory circuit that stores a predetermined potential by reset operation and initialization operation is provided with a circuit that rewrite data in the memory circuit in accordance with supply of a trigger signal. The semiconductor device has a structure in which a current flowing through the semiconductor device is supplied to a load by rewriting data in the memory circuit, and thus can function as a thyristor.