A pixel suitable for constant current operation of an active matrix type EL display device. The pixel comprises a first switch of which one terminal is connected to a source signal line whereas another terminal is connected to a current-voltage conversion element, a second switch of which one terminal is connected to the current-voltage conversion element whereas another terminal is connected to a voltage storage means and a voltage-current conversion element, a pixel electrode which is connected to the current-voltage conversion element and the voltage-current conversion element, and a third switch of which one terminal is connected to the pixel electrode whereas another terminal is connected to the power source line.