By altering amino acid sequences, the present inventors successfully produced constant regions that can confer antibodies with particularly favorable properties for pharmaceutical agents. When used to produce antibodies, the altered constant regions produced according to the present invention significantly reduce heterogeneity. Specifically, the antibody homogeneity can be achieved by using antibody heavy chain and light chain constant regions introduced with alterations provided by the present invention. More specifically, the alterations can prevent the loss of homogeneity of antibody molecules due to disulfide bond differences in the heavy chain. Furthermore, in a preferred embodiment, the present invention can improve antibody pharmacokinetics as well as prevent the loss of homogeneity due to C-terminal deletion in antibody constant region.