A circumferential area of a liquid-crystal cell is provided with a common wiring, a gate wiring, a source wiring, and an alignment film. The alignment film is insulated from the gate wiring and the source wiring by an insulating film. The common wiring is provided with a common-potential exposure portion through an opening formed on the insulating film and electrically connected with the alignment film. Because a common potential close to an average potential of cells is supplied to the alignment film, it is possible to prevent screen display troubles and deterioration caused by impurity ions remaining on the surface or the inside of the alignment film.