<p>It is intended to provide a method whereby a protein can be separated and purified at a high accuracy by a convenient procedure. A sample containing the desired protein is brought into contact with an ion exchanger under first conditions at a high ionic strength and at p H value not in the vicinity of the isoelectric point of the desired protein. Next, the component adsorbed by the ion exchanger is eluted under second conditions at a lower ionic strength than in the first conditions and at a pH value closer to the isoelectric point of the desired protein than in the first conditions.</p>
