A method of manufacturing a solid electrolytic capacitor, including: a step (A) of providing a conjugated conductive polymer-containing dispersion by polymerizing, in a dispersion medium containing seed particles turned into protective colloid by a polyanion or in a dispersion medium containing the polyanion, a monomer for obtaining a conjugated conductive polymer; a step (B) of preparing a dispersion containing a morpholine compound and the conjugated conductive polymer by adding the morpholine compound to the conjugated conductive polymer-containing dispersion; a step (C) of causing the dispersion to adhere to a porous anode body formed of a valve metal having a dielectric film on a surface thereof; and a step (D) of forming a solid electrolyte layer by removing the dispersion medium from the dispersion containing the morpholine compound and the conjugated conductive polymer, the dispersion adhering to the porous anode body.