Abstract: A solid electrolytic capacitor, including: a solid electrolytic layer; and a dielectric layer on which the solid electrolytic layer is formed. The solid electrolytic layer is formed by applying and drying a conductive-polymer solution including a conductive polymer on the dielectric layer, and the dielectric layer is formed by oxidizing a surface of an anode metal. The conductive polymer has a volume average particle size of smaller than 26 nm. A stacked aluminum electrolytic capacitor including a test solid electrolytic layer and a test dielectric layer, the test solid electrolytic layer being formed by applying and drying the conductive-polymer solution on the test dielectric layer, the test dielectric layer being formed by oxidizing a surface of aluminum having an electrical capacitance of 95 ?F/cm2, has a rate of exhibited capacitance of no less than 70%.

Abstract: A solid electrolytic capacitor in which a solid electrolytic layer is formed by applying and drying a conductive-polymer solution which contains a conductive polymer that satisfies following condition (A) and which meets following condition (B) to a dielectric layer formed by oxidizing the surface of an anode metal. Condition (A): Out of one or more peaks that appear when particle size distributions are measured by a dynamic light-scattering method using a conductive-polymer solution containing 1 mass % conductive polymer, the volume average particle size in the distribution that includes the peak of the smallest particle size is smaller than 26 nm.