The present invention provides a benzimidazole compound represented by Formula (I) ##STR00001## wherein X.sup.1 is oxygen or carbonyl, and R.sup.1 is a furan ring having 1 to 3 substituents or a pyrrole ring that may have 1 to 3 substituents; excluding compounds represented by Formula (I) wherein at least one of the substituents is a phosphoric acid group or a phosphoric ester group; or a salt thereof. The benzimidazole compound or salt thereof has excellent prostaglandin synthase inhibitory activity, and is useful as an agent for preventing and/or treating diseases in which prostaglandin D2 or metabolites thereof participates, such as allergic and inflammatory diseases, and as inhibitor for the exacerbation of Alzheimer's disease or cerebral damage.