The present invention provides a human anti-±9 integrin antibody or an antibody fragment which specifically recognize human ±9 integrin and mouse ±9 integrin, inhibit interaction with their ligands, particularly, the antibody or antibody fragment which recognize loop regions of human and mouse ±9 integrins, a gene encoring the antibody or antibody fragment, a recombinant expression vector containing the gene, a transformant harboring the gene, production method of human anti-±9 integrin antibody or antibody fragment using the transformant, and an agent for the prophylaxis or treatment of rheumatoid arthritis which contains the antibody or antibody fragment.
