A document management system includes a document processing apparatus which performs processing, such as editing of a document; and a document management server which manages division and combining of the document thus created. The document processing apparatus transmits an XML document thus created to the document management server, and requests to store the document. In this stage, in a case that the XML document includes proper nouns, the proper nouns are stored in the form of a separate file. Upon reception of a request from the document processing apparatus to acquire the XML document stored in the document management server, the document management server certifies the user of the requesting document processing apparatus. Then, the document management server combines the proper nouns with the XML document in an appropriate manner according to the certification level, and transmits the XML document thus combined to the document processing apparatus.