An active-matrix selfluminous display device has a pixel drive circuit such that the variation of the threshold voltage of a transistor for controlling the current of a luminescent device and the variation of the luminescence threshold voltage of the luminescent device are suppressed, and thereby the variation of the luminescence of the luminescent device is suppressed. An optical sensor for detecting emission of a luminescent element is connected in series with a resistor. The threshold voltage of the transistor is measured from the potential at the node. A transistor controlled by means of the signal of the optical sensor is provided so as to measure the luminescence threshold voltage of the luminescent element.
