A display device is provided with a display panel, and a source driver and a gate driver both for driving the display panel and includes a nonvolatile memory for storing a test sequence representing the procedures for a display test and testing patterns to be displayed in the display test and a control section for, in accordance with a test control signal supplied externally, controlling the source driver and the gate driver so as to display the testing patterns on the display panel in accordance with the test sequence. Since the test sequence and the testing patterns are stored in the nonvolatile memory of the display device, this eliminates the need for cumbersome and extensive tasks of preparing testing devices respectively corresponding to the models of the display device and a great number of complex data of the test sequence and the testing pattern which are respectively suitable for the models of the display device and storing them in the testing devices, respectively. That is, it is possible to drastically reduce preparations for a display test.