An object is to provide a semiconductor device capable of accurate data retention even with a memory element including a depletion mode transistor. A gate terminal of a transistor for controlling input of a signal to a signal holding portion is negatively charged in advance. The connection to a power supply is physically broken, whereby negative charge is held at the gate terminal. Further, a capacitor having terminals one of which is electrically connected to the gate terminal of the transistor is provided, and thus switching operation of the transistor is controlled with the capacitor.