The invention provides imidazopyridine derivatives represented by the general formula [I] [in which R.sup.1 and R.sup.2 may be the same or different and stand for C.sub.1-6 alkyl or the like, R.sup.3 and R.sup.4 stand for hydrogen atom, methyl group or the like, W stands for mono- or bi-cyclic 3- to 8-membered aromatic or aliphatic heterocycle or the like, and Ar stands for optionally substituted aromatic heterocycle or the like]. These compounds act as melanin-concentrating hormone receptor antagonist and are useful as medicines for central nervous system disorders, cardiovascular system disorders and metabolic disorders.