Abstract: With the purpose of forming an anodic oxide coating that is given conductivity or other new functions on the surface of aluminum-based material with high productivity, anodizing of aluminum-based material (2) is performed in an anodizing bath containing sulfuric acid together with nitrate ion to form a porous anodic oxide coating on the surface of the aluminum-based material (2). In another processing step, if electroplating is performed after anodizing, silver or a silver compound or other metal (7) can be electroplated from an electroplating bath without dissolving and removing the barrier layer from the bottom (6) of the pores (3) of the porous anodic oxide coating (1).