The prolactin production inhibition agent of the present invention containing a condensed cyclic compound, which is characterized by containing a condensed bicyclic structure of an optionally substituted homo or hetero 5- to 7-membered ring with an optionally substituted homo or hetero 5- to 7-membered ring, or a salt thereof, can be used, as a medicine, for the prophylaxis or therapy of diseases accompanied with an excess prolactin production or diseases having enhanced reactivity with prolactin, or is useful for inhibiting puerperal lactation, and also useful as a prophylactic or therapeutic agent of galactorrhea, hyperprolactinemic ovulation disturbance, amenorrhea-galactorrhea syndrome, prolactinoma, and besides, interbrain tumor, and acromegaly, pituitary gigantism.