When an electrical characteristic of the TFT varies, display unevenness such as brightness unevenness or gradation unevenness is occurred in a display image. According to the present invention, a display device in which variation of an electrical characteristic of a TFT is reduced, and display unevenness is reduced is provided. To obtain the display device, the fluctuation ratio of ON current value in a saturation region of adjacent TFTs is set to be equal to or less than .+-.12% in a TFT array substrate in which a plurality of TFTs are arranged.