To efficiently provide functions included in plural document management systems without allowing a user to be conscious of plural document management systems.

An operation input means 9 receives information for specifying a document to be processed and a command including processing contents for the document, an overall control means 1 specifies a document management system having a function for executing the processing contents included in the command based on the information of document functions included in respective document management systems managed by a document management system information managing means 5, and when the document specified by the command is managed by the specified document management system, allows the system to process the document. If the specified document is managed by another document management system, the document is moved to the specified document management system and processed. Thereby a user can execute required processing for the document only by inputting the information for specifying the document and the command including the processing contents of the document without being conscious of plural document management systems.