A file server stores storage management information and migration policy information. The storage management information includes information that indicates a storage attribute for each storage apparatus. The migration policy information includes a plurality of information sets. Each of the information sets includes information that indicates a condition of a file attribute and information that indicates a condition of a storage attribute of a storage apparatus that is a migration destination. The file server specifies a migration target file, specifies a storage apparatus that conforms to the storage attribute condition indicated by the information set that includes the information indicating a condition of a file attribute that conforms to that of a file attribute of a target file based on the storage management information, and migrates a target file from a storage apparatus that has stored the target file to the storage apparatus that has been specified.