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], R 1 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； R 2 represents a hydrogen, an alkyl, cycloalkyl, or alkoxy optionally substituted by a halogen, or a heteroaryl optionally substituted by an alkyl； X represents CR 3 , and Y represents N or CR 4 , or X represents N, and Y represents CR 4 ； and Z represents CR 5 or N.
