Disclosed is a display device including: a substrate; a first insulating film over the substrate, the first insulating film exposing a part of the substrate to provide an exposed surface to the substrate; a second insulating film in contact with the exposed surface and a first side surface of the first insulating film; and a first wiring over the second insulating film and in contact with the exposed surface, the first insulating film, and the second insulating film. The display device may further possess a third insulating film spaced from the second insulating film and in contact with the exposed surface. The first insulating film has a second side surface opposing the first side surface through the exposed surface. The third insulating film may be in contact with the second side surface, and the wiring may be located over and in contact with the third insulating film.