A mixed mode antibody affinity separation matrix comprises an antibody affinity ligand and a cation exchange group on a single separation matrix. According to such a matrix in the first step of a process for purifying an antibody or an Fc-containing target molecule, the antibody as the main target substance of the affinity purification can be purified at high purity, the selective separation properties of monomers can also be improved; and the burden on a subsequent impurity removal step can be reduced with respect to the removal of impurities such as aggregates.