A capacitor of the present invention employs one of i) polyimide directly formed by electrodeposition, ii) organic high polymer having a specific structure formed by electrodeposition, and iii) a composite film of the organic high polymer and oxide film of a conductor as dielectrics formed on the surface-roughened conductor. The organic high polymer used in the present invention contains carboxylic radical in its molecular structure. The capacitor of the present invention further comprises an opposite electrode at least containing conductive high polymer on the dielectrics. This conductive high polymer is formed by chemical oxydation-polymerization or both chemical oxydation-polymerization and electro-polymerization. The capacitor element as configured above is strong to mechanical stress, and possible to apply pressure during lamination. By laminating many of capacitor elements as configured above, a capacitor with large capacitance but small equivalent serial resistance, small leak current, and good frequency characteristics is obtained. A method for manufacturing capacitors of the present invention comprises the steps of forming a dielectric layer made of organic high polymer or a composite film of the organic high polymer and oxide film of conductor on a surface-roughened conductor; forming an insulating layer at least on the conductor; forming an opposite electrode on said dielectric layer to manufacture capacitor elements; and laminating more than one capacitor elements and connecting each other to form a laminated capacitor.