Abstract: An electrode structure which provides adhesiveness between an aluminum material, as a base material, and a dielectric layer, and adhesiveness between the dielectric layers, and enables a high capacitance, even with a thick dielectric layer. An interposing layer is formed in at least one part of a region of the surface of the aluminum material between the aluminum material and the dielectric layer and includes aluminum and carbon. The dielectric layer includes dielectric particles including valve metal, and an organic substance layer formed on at least one part of a surface of the dielectric particle. A mixture layer of dielectric particles, including the valve metal and a binder, is formed on a surface of the aluminum material, and thereafter, the aluminum material is heated in a state where the aluminum material is placed in a space including a hydrocarbon-containing substance.