The present invention provides a solid electrolytic capacitor with low leakage current. In the solid electrolytic capacitor, an anode has an anode lead made of tantalum, a surface layer made of niobium formed on the anode lead, and a rectangular block shaped base body having a porous sintered body made from niobium particles, and the anode lead is partially embedded in the base body. Onto the anode, an oxide layer made of niobium oxide, an electrically conductive polymer layer, and a cathode laminated with a first electrically conductive layer and a second electrically conductive layer are sequentially laminated. Onto the top surface of an area surrounding the cathode, a cathode terminal is formed through an electrically conductive adhesive layer. Also, an anode terminal is connected onto an edge of the anode lead.