The present invention provides: a novel compound which has a useful pharmacological action for treating heart failure or shock without increasing heart rate； and a pharmaceutical composition using the same. The present invention relates to a diphenylmethyl piperazine derivative represented by general formula (I) (In the formula R is a hydrogen atom or a hydroxy group. R is a hydrogen atom a halogen atom a hydroxy group an alkyl group having one to five carbon atoms or an alkoxy group having one to five carbon atoms excluding the case where R is a hydroxy group and R is a chlorine atom.) or a pharmaceutically acceptable salt thereof and a pharmaceutical composition containing the same. (I)
