A document management system can access a necessary document fast when necessary and accurately limit access in accordance with various security levels. An access control list shown in FIG. 2 mainly functions when access to a document is limited. One row in the access control list includes a plurality of fields which are described at the head row of each column. Information in each field included in one row (record) indicates the overall information necessary for setting predefined access control to the document including one character string. A “character string” field means that the document including the character string described in the field, of many documents stored in a database, is a document to which the access is limited.