TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The acidic compound includes polyphosphoric acid (including diphosphoric acid, pyrophosphoric acid, triphosphoric acid and polyphosphoric acid), a hydroxy compound of formula (I), a carboxy compound of formula ((HOOC-A1-COOH) or (II)) , or sulfonic acid compound, which is substituted with an aryl group or an alkyl group.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The reducing agent includes a thioether compound, a succinimide compound of formula (R1-C(=O)-N(OH)-C(=O)-R2), a polyol compound of formula (HO-A2-OH), a hydroxamic acid compound of formula (R3-C(=O)-N(R4)-OH) and a hydroxyamine compound of formula ((R5)N(R6)(OH)). The thioether compound is methylsulfanylmethane, ethylsulfanyl-ethane, 2-propylsulfanyl-ethanol, 3-(2-propylsulfanyl-ethylsulfanyl)-propionic acid methyl ester, methylsulfanyl-benzene or phenylsulfonyl-benzene. The layer containing an acidic compound or a reducing agent is disposed on a side that is farther from the support than the layer containing the electro-conductive polymer. The acidic compound or reducing agent is present at 0.00001-10 g/m2. The ratio of the acidic compound/reducing agent to the electro-conductive polymer ((acidic compound or reducing agent):(electro-conductive polymer)) is 0.0001:1.0 to 500:1 by mass ratio.R = sulfo group, halo, alkyl, aryl, -COOH or alkoxycarbonyl;R1, R2 = H, alkyl, aryl, heteroaryl, polyvinyl, polypropylene or polystyrene;R3 = H, alkyl, aryl, heteroaryl, alkoxy or aryloxy;R4 = H, alkyl, aryl or heteroaryl;R5, R6 = H, alkyl, aryl, heteroaryl, alkoxy or aryloxy;A1 = single bond or a divalent linking group;A2 = divalent linking group;n = 1-6; andm = 0-5..    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The electro-conductive polymer: is polythiophene or its derivative; and includes poly(3,4-ethylenedioxy)thiophene. The electro-conductive polymer layer further contains polystyrene sulfonic acid. EXAMPLE - An aqueous dispersion (containing poly(3,4-ethylenedioxy)thiophene and polystyrene sulfonic acid) was coated on a polyester film by use of a coater, and dried. A thickness of a resulted layer was 200 nm. A content of poly(3,4-ethylenedioxy)thiophene in the aqueous dispersion was 3.9% by mass. An aqueous solution of polyphosphoric acid (10 mass%) was then coated on it with the coater and dried. A thickness of a layer containing polyphosphoric acid was 1.8 mu m. By estimating from the concentration of the coating solution and the thickness of the formed layer, a mass ratio of poly(3,4-ethylenedioxy)thiophene to polyphosphoric acid was 1:9 and a coating amount of polyphosphoric acid was 1.8 g/m2. The resulted product was electro-conductive polymer material.