Provided is a backup system including a storage system and a backup server, in which the backup server includes a ledger for managing a copy number and a backup acquisition date and time for each backup image, a data volume that stores data accessed by a business server, a backup image volume that stores a plurality of backup images at different time points of the data volume, an access volume having a volume ID for accessing the backup image from the backup server, and a data protection area including at least one volume having an internal volume ID instead of the volume ID for accessing from the backup server are configured in the storage system, and the backup image stored in the data protection area and the access volume are associated, and the backup image in the data protection area is provided to the backup server.