An object is to provide a three-dimensional display device capable of displaying bright images with low power consumption. The display device includes: an image display portion including a pixel portion provided with a plurality of pixels; a light-blocking portion including a first shutter and a second shutter; a signal source outputting the common potential; and a controller controlling transmittances of the first shutter and the second shutter and level of the common potential output from the signal source to bring the transmittances and the level into synchronism with supply of an image signal, display of a right-eye image, or display of a left-eye image performed in the pixel portion.