Provided is a liquid crystal display device having a pixel including a transistor and a liquid crystal element and a protection circuit electrically connected to one of a source and a drain of the transistor through a data line. The protection circuit includes a first terminal supplied with a first power supply potential and a second terminal supplied with a second power supply potential higher than the first power supply potential. In a moving image display mode, an image signal is input from the data line to the liquid crystal element through the transistor, and the first power supply potential is set at the first potential. In a still image display mode, supply of the image signal is stopped, and the first power supply potential is set at the second potential. The second potential is substantially the same as the minimum value of the image signal.