On a transparent substrate to which a gate electrode is arranged, a silicon nitride film and a silicon oxide film to be gate insulating films are deposited, and further, a polycrystalline silicon film as a semiconductor film to be an active region is formed. On the polycrystalline silicon film corresponding to the gate electrode, a stopper is arranged, and a silicon oxide film and a silicon nitride film to be an interlayer insulating films are deposited so as to cover this stopper. The film thickness T0 of the stopper is set in a range of 800 angstroms to 1200 angstroms. Furthermore, the film thickness T0 of the stopper is set in the range to fulfill the following expression: T0+T1≦(T2×8000 Å)½ where T1 is the film thickness of the silicon oxide film and T2 is the film thickness of the silicon nitride film.