Disclosed are an Fc fragment modified by a non-peptide polymer, a pharmaceutical composition comprising the Fc fragment modified by the non-peptide polymer as a carrier, a complex of the Fc fragment and a drug via a linker and a pharmaceutical composition comprising such a complex. The Fc fragment modified by a non-peptide peptide according to the present invention lacks immunogenicity and effector functions. Due to these properties, the Fc fragment maintains the in vivo activity of a drug conjugated thereto in high levels, remarkably increases the serum half-life of the drug, and remarkably reduces the risk of inducing immune responses.