The present invention provides an antibody that can bind to targets with greater affinity. A flexible antibody-like molecule having a nonpeptide hinge part comprising: a group having a nonpeptide hinge part represented by a general formula (I): XY-Asp-Lys-Thr-His-Thr (SEQ ID No. 1)—wherein X represents an amino acid or a peptide composed of 2 to 50 amino acid residues, and Y represents for a group having an alkyleneoxide; and an antibody Fc fragment bound to the group having a nonpeptide hinge part.