Tricyclic compound and jak inhibitor

Provided is a novel tricyclic compound which has JAK (Janus kinase) inhibitory activity and is especially useful for prophylaxis, treatment or amelioration of autoimmune diseases, inflammatory diseases and allergic diseases. A 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.