Disclosed are: a peptide capable of binding to an immunoglobulin a fusion protein of the peptide nucleic acids encoding the peptide and the fusion protein, respectively production methods for the peptide and the fusion protein, respectively a composition and a means for binding an immunoglobulin a pharmaceutical composition for the treatment or prevention of a disease induced by the binding between C1q and an immunoglobulin, which comprises a peptide capable of binding to the immunoglobulin or a fusion protein of the peptide and others.
