Provided is a method of manufacturing a solid electrolytic capacitor including a capacitor element, the capacitor element having an anode body with a dielectric coating film formed on a surface thereof and a solid electrolyte made of a conductive polymer. The method includes the steps of: forming the capacitor element having the anode body with the dielectric coating film formed on the surface thereof; preparing a polymerization liquid A containing one of a monomer as a precursor of the conductive polymer and an oxidant, and a silane compound; preparing a polymerization liquid B by adding the other of the monomer and the oxidant that is not contained in polymerization liquid A, to polymerization liquid A; and performing polymerization after impregnating the capacitor element with polymerization liquid B.