PURPOSE: To reduce a mask process by a method wherein the metal surface of a drain electrode and a drain bus is oxidized anodically and an oxide film, of a dense structure, which has been formed on the surface of a metal layer is used as a mask in order to remove the metal layer at a display electrode part.

CONSTITUTION: By utilizing a terminal at the peripheral edge part of a liquid- crystal display element substrate, a drain electrode 24a and a drain bus are oxidized anodically. At this time, the drain electrode 24a and an Al layer 24b are connected via a semiconductor active layer 16, but they are in reality in an insulated state because the semiconductor active layer 16 formed of undoped amorphous silicon is at a high resistance. As a result, an anodic oxidation film 26 is formed only on the surface of the drain electrode 24a and the drain bus. When this assembly is immersed, e.g. in a phosphoric acid-based etchant, only the Al layer 24b is etched, and an ITO film 22b to be used as a display electrode is revealed. At this time, the anodic oxidation film 26 of a dense structure functions as a mask; the drain electrode 24a and the drain bus are not etched.