Provided is an IL-18 receptor antibody usable for immunohistochemistry, which functions as an IL-18 receptor antagonist. Also provided is a pharmaceutical composition and method for preventing and/or treating an IL-18-dependent disorder, particularly skin thickening caused by ultraviolet, using the antibody. An antibody against the IL-18 receptor ± subunit, which is characterized by binding specifically to a polypeptide consisting of the amino acid sequence shown by SEQ ID NO:1, or an antibody against the IL-18 receptor ² subunit, which is characterized by binding specifically to a polypeptide consisting of the amino acid sequence shown by SEQ ID NO:2, is prepared.
