Since both a physical storage place and a logical storage place in a storage system are separately managed as a directory structure, or a hierarchical structure, even in such a case that the physical storage place has been changed, the logical storage place which is displayed to the user is not changed, and thus, the user can use the file while the user need not become aware of the change of the file. When the contents of a file is displayed, a physical storage destination of the file is acquired based upon both a reference path and a relative path of the file, and then, the file is acquired from the physical storage destination.