[Problem] To provide compounds useful as preventives or remedies for circular system disorders, nervous system disorders, metabolic disorders, reproduction system disorders, digestive system disorders, neoplasm, infectious diseases, etc., or as herbicides.[Means for Solution] A long-chain fatty acyl elongase inhibitor comprising, as the active ingredient thereof, a compound or a pharmaceutically-active salt thereof of a formula (I): [wherein W represents a hydrogen atom, a C1-6 alkyl, etc.; X represents an aryl, a heteroaryl, etc.; n indicates 0 or 1; Z represents a hydrogen atom, a C1-6 alkyl, etc.; A1, A2, A3 and A4 each independently represent CH or N].