The source storage 1220 and source path 1230 constituting backup source information of all of the backup data in a computer system 1000, the destination storage 1240 and destination path 1250 constituting backup destination information and information regarding the backup time-point 1260 are held on an administration console 1010; a backup manager 1020 that runs on the administration console 1010 designates backup between the NAS's and gives instructions for restoration from the backed-up data by using these items of information.