It is intended to provide a novel compound or a salt thereof, or crystals of the compound or the salt, which inhibit Axl and are useful in the treatment of a disease caused by hyperfunction of Axl, the treatment of a disease associated with hyperfunction of Axl, and/or the treatment of a disease involving hyperfunction of Axl. [Solution] The present invention provides a pyridone derivative having a tetrahydropyranylmethyl group represented by the following formula (I) having various substituents, or a salt thereof, or crystals of the compound or the salt (wherein R 1 , R 2 , R 3 , R 4 , R 5 , W, X, Y, and Z are each as defined in the specification).