A compound represented by the formula [I]: [wherein R.sup.1 and R.sup.2 are the same or different and each represents C.sub.1-6 alkyl, C.sub.3-8 cycloalkyl, et al; R.sup.3a, R.sup.3b, and R.sup.4 are the same or different and each represents hydrogen, C.sub.1-6 alkyl, et al; X represents --N--, --CH--, et al; Y, represents a single bond, C.sub.1-3 alkylene, et al; Y.sub.2 represents C.sub.1-4 alkylene, oxy(C.sub.1-4 alkylene), et al; Ar.sub.1 represents a monocyclic aromatic carbocyclic group, monocyclic aromatic heterocyclic group, et al; and Ar.sub.2 represents a 5- or 6-membered aromatic carbocyclic group, aromatic heterocyclic group, et al]. This compound functions as a melanin-concentrating hormone receptor antagonist and is useful as, e.g., a therapeutic agent for obesity, et al.