The main purpose of the invention is to provide a novel aromatic heterocyclic derivative or a pharmaceutically acceptable salt thereof. Examples of the invention include aromatic heterocyclic derivatives represented by general formula [1] and pharmaceutically acceptable salts thereof.In formula [1]: R1 represents phenyl optionally substituted with one or two groups selected from the group consisting of halogens, as well as alkyls and alkoxys optionally substituted by halogens； R2 represents hydrogen, an alkyl, cycloalkyl, or alkoxy optionally substituted by a halogen, or a heteroaryl optionally substituted by an alkyl； X represents CR3, and Y represents N or CR4, or X represents N, and Y represents CR4； and Z represents CR5 or N.
