To provide an antibody useful for capturing a biotin-labeled substance used for immunity measurement etc.

A spacer comprising a spacer moiety which is between a biotin moiety and an active group and contains a longer peptide bond than a conventionally used compound is used and bound to N-hydroxysuccinimide through an ester linkage. The resultant ester is bound to a carrier protein and used as an immunogen to carry out immunization. Thereby, the resultant hybridoma produces a monoclonal antibody having high reactivity to the antibody in which the biotin is bound and low reactivity to free biotin.