A benzimidazole derivative or its medically acceptable salt, represented by the following formula (1), that is a human chymase activity inhibitor capable of being applied clinically: wherein, R1 and R2 represent a hydrogen atom, an alkyl group or an alkoxy group, etc., A represents an alkylene group or an alkenylene group, E represents —COOR3, —SO3R3, —CONHR3 or —SO2NHR3, etc., G represents an alkylene group, M represents a single bond or —S(O)m—, J represents a heterocyclic group, and X represents —CH═ or a nitrogen atom.