The present invention aims at provision of a quinoline derivative having a neurokinin 2 (NK2) receptor antagonistic action and relates to a compound represented by the formula (I) ##STR00001## wherein R.sup.1 is a hydrogen atom and the like; R.sup.2 is a hydrogen atom, a hydrocarbon group optionally having substituent(s) and the like; R.sup.3 is unsubstituted (i.e., absence), a hydrogen atom and the like; R.sup.4 and R.sup.5 are the same or different and each is a hydrogen atom, a hydrocarbon group optionally having substituent(s), and the like; R.sup.6 is (cyclic group optionally having substituent(s))-carbonyl, and the like; R.sup.7, R.sup.8, R.sup.9 and R.sup.10 are the same or different and each is a hydrogen atom, halogen and the like; or R.sup.7 and R.sup.8, R.sup.8 and R.sup.9, and R.sup.9 and R.sup.10 may form a ring together with the adjacent carbon atoms; n is an integer of 1 to 5; represents unsubstituted (i.e., absence) or a single bond; and represents a single bond or a double bond, or a salt thereof, and the like.