In a document management system according to the present invention, which is used for registering and managing a document in a database of a relational database server, a judgment is made as to whether or not a capacity of the database has reached a predetermined limited capacity, and when it is judged that the predetermined limited capacity has been reached, an identifier indicating an editing-inhibited state is added to the database, to inhibit all editing actions to the database, thereby achieving the user-friendly system.