Spiro compounds of the general formula (I): wherein Ar1 represents an optionally substituted aryl or heteroaryl; n represents 0 or 1; T, U, V and W each represent a nitrogen atom or an optionally substituted methine group, wherein at least two of which represent said methine group; X represents methine; Y represents an optionally substituted imino or oxygen atom. These novel spiro compounds exhibit neuropeptide Y receptor (NPY) antagonistic activities and are useful as agents for the treatment of various diseases related to NPY, for example, cardiovascular disorders, central nervous system disorders, metobolic diseases and the like.