A semiconductor device suitable for low-voltage driving. The semiconductor device includes a first transistor, a second transistor, a power supply line, a circuit, and a memory circuit. The first transistor controls electrical continuity between the circuit and the power supply line. The memory circuit stores data for setting a gate potential of the first transistor. The second transistor controls electrical continuity between an output node of the memory circuit and a gate of the first transistor. The second transistor is a transistor with an ultralow off-state current, for example, an oxide semiconductor transistor. In a period for operating the circuit, a first potential is input to the power supply line and the second transistor is turned off. In a period for updating the gate potential of the first transistor, a second potential is input to the power supply line. The second potential is higher than the first potential.