A display device of at least one 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 is provided with a first flag for specifying a polarity of voltage of a common electrode. The display driver extracts the first flag from the serial data in accordance with a timing of a serial clock, and performs display in accordance with the image data, while generating the voltage of the common electrode which voltage has the polarity specified by the first flag extracted. This realizes a display device capable of generating a timing signal for AC common voltage, while having a small circuit.