Provided is a storage control system enabling the prompt execution of data backup from a primary storage to a backup device, and capable of backing up data of the primary storage in the backup device without having to use a backup server. This storage control system has a host system; a storage device having a data volume storing data to be exchanged with the host system, a replication volume of the data volume, and a difference data volume configured independently from the data volume and which stores difference data in relation to the data volume; and a backup device having a backup volume storing backup data of the replication volume and the difference data volume; wherein the host system has a backup control module for recognizing the difference data volume of the storage device apart from the data volume, and backing up the difference data volume in the backup volume.