Compounds represented by general formula (I), (wherein ring A and ring B are in a state of ortho fusion, the ring A representing an aromatic carbocyclic or heterocyclic ring, and the ring B representing a four- to seven-membered aliphatic carbocyclic or nitrogen-containing heterocyclic ring wherein the nitrogen atom can be present in only the site of fusion with the ring A; Ar represents an aromatic carbocyclic or heterocyclic group optionally substituted with a group selected among halogen atoms and lower alkyl, lower alkenyl, halogenated lower alkyl, lower alkoxy, lower alkylthio, lower alkylamino, di(lower alkyl)amino, and aromatic carbocyclic groups; and R represents a substituent selected among halogen atoms, nitro, lower alkyl, lower alkoxy, aromatic carbocyclic groups, and a carbonyl group having an aromatic carbocyclic group, or a hydrogen atom, provided that when the group represented by formula (a), is the group represented by formula (b), Ar represents neither phenyl nor 4-chlorophenyl) or salts thereof; a process for preparing the same; and a therapeutic agent for bulimia, obesity, or diabetes, comprising the compound or salt thereof as the active ingredient.