The display device includes a timing controller, a data driving unit, a gate driving unit, and a display panel. The timing controller divides m-bit image data (m is a natural number) received from the outside into n different image data for each viewpoint (n is 2 or larger natural number), and generates an output frame composed of a plurality of 3-dimensional image data including the n image data for each viewpoint. Then, the output frame is dithered so that the image data for each viewpoint expresses m-bit gradation with l bit, and image data for each viewpoint included in the output frame are outputted as output image signals.