PURPOSE: To prevent the generation of bending, and to reduce the number of processes and the cost, by composing an electrode unit which is made by incorporating a metal plate electrode furnishing slits or cuttings in one direction and an insulating layer.

CONSTITUTION: Since an electrode plate 50 is a pattern in which a specific etching pattern has rigidity in the X direction, plural cuttings 51 are formed particularly. By the function of the cuttings 51, the electrode plate 50 loses the rigidity in the X direction. A spacer 52 is the only member to have the rigidity in the X direction, of the materials to compose the laminate electrode unit. Since an electrode plate 53 has a specific etching pattern which has lost the rigidity in the X direction already, it is not necessary to form slits or cuttings particularly. Since the rigidity in the X direction of the electrode unit produced by laminating and baking the above materials depends on only the spacer 52, no bending is produced by the thermal expansion and the like.