To provide a memory element which keeps a stored logic state even without supply of power. To increase an effect of reducing power consumption by facilitating stop of supply of power to the memory element for a short time. Data (potential) held in a node in a logic circuit can be swiftly saved on a node where one of a source and a drain of the transistor and one electrode of the capacitor included in a memory circuit are connected by lowering a potential of the other electrode of a capacitor before a transistor is turned on. By making a potential of the other electrode of the capacitor when the transistor is in an off state higher than a potential of the other electrode of the capacitor when the transistor is in an on state, a potential of the node can be reliably held even without supply of power.