The present inventors discovered that the half-life in blood of an IgG antibody which is a polypeptide comprising an FcRn-binding domain can be controlled by controlling the surface charge through modification of residues exposed on the surface among residues in the variable regions of the IgG antibody. Antibodies whose half-life in blood had been controlled by the methods of the present invention were confirmed to actually retain the original activity. The methods of the present invention are widely applicable to polypeptides comprising an FcRn-binding domain, such as IgG antibodies, which are recycled via the FcRn salvage pathway regardless of the type of target antigen.
