In order to use an auxiliary wiring 4 formed on one of opposing substrates as a bypass line of one of circuit lines arranged in matrix on the same substrate, which has a broken portion, cross points (A and B) of the auxiliary wiring 4 and the broken circuit line are electrically connected by removing an insulating film between the auxiliary wiring and the circuit line by irradiating these cross points with a laser beam. An electrostatic protective element 10 is provided in each of cross points of the auxiliary wiring and the circuit lines and the auxiliary wiring is connected to a common terminal 13 connected to an opposing electrode formed on the other opposing substrate such that the potential of the auxiliary wiring can be removed.