A solid electrolytic capacitor that includes a valve-action metal substrate including a dielectric layer having pores on at least one main surface thereof, a mask layer made of an insulating material and covering a periphery of the main surface of the valve-action metal substrate, and a cathode layer on the dielectric layer at least within a region surrounded by the mask layer. The cathode layer includes a solid electrolyte layer on the dielectric layer, and the solid electrolyte layer includes a first layer filling the pores of the dielectric layer, a second layer on the dielectric layer and along an outer peripheral portion of the region surrounded by the mask layer, the second layer being made of a material same as or different from that of the first layer, and a third layer covering the second layer and the dielectric layer.