PURPOSE: To make storage capacity effective by constituting a new file of an original file and a different part from the original file at the formation and storage of a new file.

CONSTITUTION: When a file F2 is read out on the basis of a specification from an input device and the file F2 is decided as information based upon an old file F1 on the basis of the relation 1 to the file F2, the old file F1 is automatically read out. On the basis of relation 2, a file F0 storing information for changing positions is automatically read out and relative addresses indicating the changing points and changing data are read out. After reading out information from the files F1, F0, the data in the file F1 are changed and displayed such that '1' is changed to '0' in an item A and an item F is changed to an item G in accordance with data in a table 4.