A display device of an embodiment of the present invention is a display device of an active matrix type, and includes a display driver supplied with image data included in serial data by serial transmission. The serial data has a first flag for specifying a polarity of voltage of a common electrode added thereto. The display driver generates, in accordance with a timing of a serial clock, a timing signal for a horizontal period for a data signal line driver, and a timing signal for a gate signal line driver. This realizes a display device capable of easily generating, within a driver IC, a timing signal for writing the image data in pixels.