A novel biphenyl compound having GPR 14 antagonistic activity. It is a compound represented by the formula (I): ##STR00001## wherein R.sup.1 represents hydrogen, etc.; X represents 1 to 12 spacers; A represents amino, etc., R.sup.2 and R.sup.3 each represents a hydrocarbon group, etc.; and rings B and C each represents an optionally further substituted benzene ring, or a salt thereof.