PURPOSE: To prevent local extraordinary heating by filling a specific material into spaces of a mesh after an electrode and the mesh are welted together.

CONSTITUTION: An electrode 4 and a mesh 1 are overlapped and welted together. An EVA resin 5 mixed with carbon is filled in spaces enclosed by a part with thickness T of the mesh 1 and the electrode 4. Thus the electrode 4 and the mesh 1 are brough in electrical contact with each other entirely through the conductive resin besides the positions welted together. Accordingly, dispersion of the resistance in connection parts and local extraordinary heating due to this dispersion can be eliminated.