To provide a semiconductor device with high reliability in operation, in which data in a volatile memory can be saved to a non-volatile memory. For example, the semiconductor device includes an SRAM provided with first and second data storage portions and a non-volatile memory provided with third and fourth data storage portions. The first data storage portion is electrically connected to the fourth data storage portion through a transistor, and the second data storage portion is electrically connected to the third data storage portion through a transistor. The transistors are turned off when the SRAM operates, and the transistors are turned on when the SRAM does not operate, so that data in the SRAM is saved to the non-volatile memory. Precharge is performed when the SRAM is restored.