A method is provided for enhancing the bond between the polarizable electrode layer and the undercoat layer. The method includes a first step for forming an undercoat layer on a collector and a second step for forming a polarizable electrode layer on said undercoat layer. The first step is performed by coating said collector with a coating solution for the undercoat layer that includes electroconductive particles, a first binder, and a first solvent. The second step is performed by coating said undercoat layer with a coating solution for the polarizable electrode layer that includes porous particles, a second binder, and a second solvent. The first solvent can dissolve or disperse said first and second binders. The second solvent can dissolve or disperse said first and second binders. Thefusion of the interface between the undercoat layer and the polarizable electrode layer enhances the bond therebetween.