The present invention provides a benzoazepine compound represented by following general formula (1): or a salt thereof, wherein R represents a hydrogen atom, a hydroxy group optionally protected with a protecting group, etc., R1 represents a hydrogen atom or hydroxy-protecting group, and X represents an oxygen atom or a sulfur atom. The benzoazepine compound of the present invention and salts thereof have high solubility in water, and can be suitably used for injections.