A solid electrolytic capacitor formed with a dielectric coating and a solid electrolyte layer successively formed on a surface of an anode body, wherein the solid electrolyte layer includes a conductive polymer containing at least a tetrahydronaphthalenesulfonate ion and a naphthalenesulfonate ion as dopants or a conductive polymer containing at least a tetrahydronaphthalenesulfonate ion and a benzenesulfonate ion as dopants. As a result, a solid electrolytic capacitor having a low ESR and a good heat resistance is provided.