PURPOSE: To permit any legal right executor to approach a targeted document without using a password, etc., and to perform security management in a wide range flexibly by performing the management by attaching owner information at every classification node and document.

CONSTITUTION: A new classification node name and a generating place classification node name which generates the classification node are inputted from an input device 1 by a user, and inputted information is sent to a processing part 6 via an input part 2. The processing part 6, after checking an owner by an owner managing part 8, requests the generation of a new classification node and that of a classification node owner managing file 14 to a document classification managing part 7. The document classification managing part 7 generates new classification 11 based on a generating place classification node 10 by tracing the classification node in an accumulation medium 9, and generates the classification node owner managing file 14 in the new classification node 11. Thence, the processing part 6 delivers a user name to the owner managing part 8 as the owner information, and requests the initialization of classification node owner information.