[Problem] To provide a compound which can be used as an MC 4 receptor agonist. [Means for Solution] The present inventors have investigated MC 4 receptor agonists, and have found that a piperazine derivative has an action related to the agonists, thereby completing the present invention. That is, the piperazine derivative of the present invention has an MC 4 receptor agonistic action, and can be used as an agent for preventing or treating bladder and/or urinary tract diseases, in particular, underactive bladder, hypotonic bladder, acontractile bladder, detrusor underactivity, neurogenic bladder, urethral relaxation failure, detrusor-external urethral sphincter dyssynergia, and voiding dysfunctions in benign prostatic hyperplasia.
