An antibody specifically recognizing human .alpha.9 integrin (in particular, a monoclonal antibody); a chimeric antibody, a humanized antibody and a human antibody; a hybridoma cell producing the monoclonal antibody as described above; a method of producing the monoclonal antibody as described above; a method of producing the hybridoma cell as described above; a therapeutic containing the antihuman .alpha.9 integrin antibody as described above; a diagnostic containing the antihuman .alpha.9 integrin antibody as described above; a method of screening a compound inhibiting the activity of human .alpha.9 integrin; and so on.