PURPOSE: To enable application to diagnosis and therapy of diseases by recognition of mammal osteoclasts and specific bonding thereto.

CONSTITUTION: Osteoclasts derived from a mammal such as a rat are cultured in an osteoclast differentiation-inducing medium at about 37°C to obtain osteoclasts excellent in bone resorption. The resultant osteoclasts are used as an immunogen and internal immunization of the mammal is carried out. The obtained antibody-producing cell such as a splenic cell is fused with a mouse-derived myeloma cell to obtain hybridomas. The resultant hybridomas are screened to select a hybridoma producing a monoclonal antibody specifically reacting only with an osteoclast. The selected hybridoma is then mass-cultured in a serum medium or a serum-free medium and the objective monoclonal antibody is recovered and produced from the supernatant of the resultant cultured material.