An objective of the present invention is to provide an Fc region variant with enhanced FcγRIIb-binding activity, and/or enhanced binding selectivity to FcγRIIb compared to FcγRIIa (type R), as compared to those of a polypeptide containing an Fe region to which an amino acid alteration(s) has not been introduced; a polypeptide which includes the Fc region variant; a pharmaceutical composition containing the polypeptide; preventing therapeutic or preventive agent for immunological inflammatory diseases that includes the pharmaceutical composition; a production method thereof; and a method of enhancing FcγRIIb-binding activity and also enhancing binding selectivity to FcγRIIb compared to FcγRIIa (type R).