A device is disclosed for testing the function of a display port. The device includes a display port transmitting part, a field programmable gate array, and a memory. The display port transmitting part transmits connecting signals to a display port timing controller mounted on a display panel. The field programmable gate array applies a test signal to the display port timing controller, and controls the connecting signals applied from the display port transmitting part to the display port timing controller. The memory has software that determines acceptance or rejection of the display port function based on data output from the display port timing controller in response to the connecting signals or the test signal.