The present invention provides a human anti-α9 integrin antibody or an antibody fragment which specifically recognize human α9 integrin and mouse α9 integrin, inhibit interaction with their ligands, particularly, the antibody or antibody fragment which recognize loop regions of human and mouse α9 integrins, a gene encoding the antibody or antibody fragment, a recombinant expression vector containing the gene, a transformant harboring the gene, production method of human anti-α9 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.