Even if a document file within a document management system has been transmitted outside the system by E-mail, a document management system maintains a document-file access rights equivalent to that within the document management system. The document distribution system distributes document files the access rights of which are managed by the document management system. The recipient of the document file is assumed to have access rights to the document file within the document management system. The document distribution system acquires policy information, which corresponds to these access rights, from a policy server. The document distribution system then transmits the acquired policy information and the document file to the recipient.