Compounds or salts thereof, or crystals thereof, areprovided which inhibit Axl and are useful for treatingdiseases caused by Axl hyperfunction, diseases associatedwith Axl hyperfunction and/or diseases accompanied by Axlhyperfunction. Pyridone derivatives represented by formula(1) having various substituents or salts thereof, orcrystals thereof (where R1, R2, R3, R5, R6, A, W, X and n inthe formula (1) are as defined in the specification,respectively) are provided.