A semiconductor device in which stored data can be held even when power is not supplied and there is no limitation on the number of writing operations is provided. A semiconductor device is formed using a material which can sufficiently reduce the off-state current of a transistor, such as an oxide semiconductor material that is a wide-gap semiconductor. When a semiconductor material which can sufficiently reduce the off-state current of a transistor is used, the semiconductor device can hold data for a long period. In addition, by providing a capacitor or a noise removal circuit electrically connected to a write word line, a signal such as a short pulse or a noise input to a memory cell can be reduced or removed. Accordingly, a malfunction in which data written into the memory cell is erased when a transistor in the memory cell is instantaneously turned on can be prevented.