To correct a document attribute, to add a document and to eliminate a document, or the like at high speed in a document management system using a detachable storage medium.

In the document management system for storing attributes of a document as well as the document information and retrieving the stored document information with the document attribute information, when the detachable storage medium with document information and a document attribute file stored therein is inserted, the document attribute file is copied into a high-speed readable and writable device. When the document attribute file copied into the high-speed readable and writable device is updated and an instruction to release the detachable storage medium is made, the document attribute file copied into the high-speed readable and writable device and updated is stored in the detachable medium.