A write control method of exclusively controlling write requests from a plurality of user terminals to an identical structured document is disclosed. The identical structured document includes a plurality of elements each containing document content. A monitor field is set in units of the elements within the identical structured document. Upon accepting one write request from one user terminal, it is determined if the one write request is directed to the document content under monitoring by referral to the monitor field. Then, the one write request is handled to reject overwriting of the document content despite the one write request if the document content has been rewritten by another write request from another user terminal in advance.