A solid electrolytic capacitor (1) comprises a capacitor element (2) which includes an anode foil (4) and a cathode foil (5) rolled with a separator (6) interposed therebetween, and a solid electrolyte layer or an electrically conductive polymer layer provided therein. The cathode foil (5) is coated with a film of a titanium-containing composite metals nitride. The composite metals nitride is aluminum titanium nitride, chromium titanium nitride, or zirconium titanium nitride.