Disclosed are a solid electrolytic capacitor comprising a valve-acting metal, an oxide dielectric layer formed on a surface of the valve-acting metal and a solid electrolyte layer provided on the dielectric film layer, in which the electrically conducting polymer composition layer contains as a dopant at least one anion selected from (1) an alkoxy-substituted naphthalene monosulfonate anion, (2) a heterocyclic sulfonate anion, and (3) an anion of an aliphatic polycyclic compound or a combination thereof with another anion having a dopant ability and a method for producing such a solid electrolytic capacitor. The solid electrolytic capacitor of the invention is excellent in voltage resistance, high frequency property, tan &dgr;, leakage current, heat resistance (reflow property), etc.