A method for recovering at least cobalt of valuable metals, cobalt and nickel, from an acidic solution obtained by subjecting waste containing positive electrode materials for lithium ion secondary batteries to a wet process, the acidic solution comprising cobalt ions, nickel ions and impurities, wherein the method includes: a first extraction step for Co recovery, the first extraction step being for extracting cobalt ions by solvent extraction from the acidic solution and stripping the cobalt ions; an electrolytic step for Co recovery, the electrolytic step being for providing electrolytic cobalt by electrolysis using a stripped solution obtained in the first extraction step for Co recovery as an electrolytic solution; a dissolution step for Co recovery, the dissolution step being for dissolving the electrolytic cobalt in an acid; and a second extraction step for Co recovery, the second extraction step being for extracting cobalt ions by solvent extraction from a cobalt dissolved solution obtained in the dissolution step for Co recovery and stripping the cobalt ions.