Provided is a novel tricyclic compound which has JAK inhibitory activity and is especially useful for prophylaxis, treatment or amelioration of autoimmune diseases, inflammatory diseases and allergic diseases. A novel tricyclic compound which is represented by formula (I), formula (II) or formula (III) (wherein each of A1, A2 and A3 represents a cyclohexane-1,4-diyl group or the like； each of L1, L2 and L3 represents a methylene group or the like； each of X1 and X3 represents O or NH； each of R1 and R3 represents a cyano C1-6 haloalkyl group or the like； and R2 represents an aromatic heterocyclic group), a tautomer or a pharmaceutically acceptable salt of the compound, or a solvate of the compound, the tautomer or the pharmaceutically acceptable salt.本發明係提供一種具有JAK抑制活性，尤其是可用於自我免疫疾病、炎症性疾病、過敏性疾病之預防、治療或改善之新穎3環性化合物。本發明提供一種以式(I)、式(II)或式(III)(A1、A2、A3意指環己烷-1,4-二基等，L1、L2、L3意指亞甲基等，X1、X3意指O或NH，R1、R3意指氰基C1-6鹵烷基等，R2意指芳香族雜環基)表示之新穎3環性化合物、該化合物之互變異構物或其醫藥上可容許之鹽或彼等之溶劑合物。
