A virtualizing file system view method for virtualizing one or more network storage devices into a virtualized file system view network storage system wherein destination network storage information of stored files is compactly held regardless of the number of files, and files are separated into one or more file groups and the file groups managed in destination network storage units. Until now, managing network storage unit information in individual files was necessary however the virtualizing file system view method reduces the management information that must be held and efficiently utilizes network storage capacity without holding destination network storage information in individual files. The cost of rewriting information is also lowered during structural changes such as adding or deleting network storage units since storage destination network information can be rewritten in file groups.