An organic EL display device of active matrix type wherein insulated-gate field effect transistors formed on a single-crystal semiconductor substrate are overlaid with an organic EL layer; characterized in that the single-crystal semiconductor substrate (413 in FIG. 4) is held in a vacant space (414) which is defined by a bed plate (401) and a cover plate (405) formed of an insulating material, and a packing material (404) for bonding the bed and cover plates; and that the vacant space (414) is filled with an inert gas and a drying agent, whereby the organic EL layer is prevented from oxidizing.