To provide a highly reliable solid electrolytic capacitor having a large capacitance and an excellent impedance characteristic, by using conductive high polymers for its solid electrolyte.

In a solid electrolytic capacitor, in which a dielectric oxide film 1a is formed on the surface of a capacitor element 1 composed of a metal 1b serving as a valve which becomes an anode, and a conductive high polymer layer is formed on the surface of the film 1a, the high polymer layer is composed of a first conductive high polymer layer 2 made of polythiophene or its derivative and a second conductive high polymer layer 3 formed by electrolyzing and polymerizing polypyrrole or its derivative. In a method for manufacturing the capacitor, the first conductive high polymer layer 2 is formed by performing chemical polymerization on a solution prepared by dissolving monomeric thiophene in a solvent containing water. In the method for manufacturing the capacitor, in addition, the layer 2 is formed by heating a solution prepared by dissolving polymeric thiophene in a solvent containing water.