A spatial light modulation device capable of displaying a large number of gray scales is provided. The inventors of the present invention proposed a spatial light modulation device having: a first structure in which a switching transistor and an erasure transistor, each having its gate electrode connected to a different scanning line, are formed in each pixel, and whose switching is controlled separately; or a second structure in which two switching transistors, each having its gate electrode connected to a different scanning line, are formed in each pixel, and whose switching is controlled separately.