Abstract: A neutralizing monoclonal antibody specifically reacting with MMP13, a method of neutralizing enzyme activity of MMP13 and an immunological measuring method each using the antibody, as well as a diagnostic agent and a pharmaceutical composition containing the antibody, are provided. Various antibodies to MMP13 have been hitherto obtained, but an antibody having neutralizing activity against MMP13 has not been obtained. The present inventors intensively studied, as a result, found out a neutralizing antibody having specificity for MMP13, resulting in completion of the present invention.