It is intended to provide a method for efficiently and stably producing a heteromultimer by incubating, under a reducing condition, homo variants of plural types of polypeptides in which the alteration of amino acids that form the interface between Fc regions and/or the alteration to destabilize the stability of a heavy chain CH3 region has been introduced in the heavy chain CH3 regions so at to achieve the promotion of the dissociation of the Fc regions and/or the control of the association thereof through the use of charge repulsion.
