Solid electrolytic capacitor and capacitor array for suppressing delamination

A solid electrolytic capacitor comprising:

• an anode plate having a porous layer on at least one main surface thereof;
• a dielectric layer on a surface of the porous layer;
• a cathode layer on a surface of the dielectric layer, wherein the cathode layer includes a solid electrolyte layer on the surface of the dielectric layer, and a conductor layer on a surface of the solid electrolyte layer, and the solid electrolyte layer includes a first solid electrolyte layer in a region including an inside of pores of the dielectric layer, and a second solid electrolyte layer covering the first solid electrolyte layer;
• a mask layer made of a first insulating material and located in a region surrounding the cathode layer at a peripheral edge of the porous layer;
• and
• a columnar layer made of a second insulating material and located at a distance from the mask layer in a region surrounded by the cathode layer in the porous layer,
• wherein, when viewed from a cross section along a thickness direction across the cathode layer, the mask layer, and the columnar layer, the first solid electrolyte layer includes an outer side portion in contact with the mask layer and an inner side portion in contact with the columnar layer and not in contact with the outer side portion, on the surface of the dielectric layer on an outermost surface of the anode plate, and
• at least a part of the second solid electrolyte layer penetrates the inside of the pores of the dielectric layer in a region between the outer side portion and the inner side portion of the first solid electrolyte layer.