The present invention provides novel benzimidazole derivatives of the following formula (I) and salts thereof:
wherein R 1 represents a lower alkyl group or a lower alkyloxy-lower alkyl group: R 2 represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 8 carbon atoms, an aryl group, and such; R 3 represents a lower alkyl group, a lower alkenyl group, an aryl group, a lower alkylaryl group, an aryl-lower alkenyl group, a halothienyl group, a lower alkylamino group, or an aryl-lower alkylamino group; A represents a benzene ring, a naphthalene ring, or a pyridine ring; and X represents a halogen atom. The derivatives and their salts have blood sugar level-depressing activity or PDE5-inhibiting activity, and are useful as pharmaceutical preparations.