Provided is a solid electrolytic capacitor including an anode body, a dielectric layer formed on the anode body, and a solid electrolyte layer that covers at least a part of the dielectric layer and includes a conductive polymer, the solid electrolyte layer including a first silicon-containing component and a second silicon-containing component, the first silicon-containing component being at least one selected from the group consisting of a first silane coupling agent and residues of the first silane coupling agent, the second silicon-containing component being at least one selected from the group consisting of a second silane coupling agent and residues of the second silane coupling agent, the first silane coupling agent including a first substituent that has a first functional group and is bonded with a silicon atom, and a hydrolytically condensable group, the second silane coupling agent including a second substituent that has a second functional group and is bonded with a silicon atom, and a hydrolytically condensable group, and the first substituent and the second substituent being different from each other.