PURPOSE: To finely control the access right for group members by providing an access level table including the definition of the access level of group members.

CONSTITUTION: An access level table 1-3 includes an access level 2-3 of group members. When judging that a command issuer belongs to the possession group of the access level table 1-3, an access level judging means 1-2 returns the access level 2-3 of group members. Consequently, the access level for access from group members to circumstances shared among members can be set to level 1, level 2, or level 3. This access level, a level 1 user condition list 2-4, and a a level 2 user condition list 2-5 are combined and used to finely control the access right of group members for circumstances shared among groups.