An integrated document management system comprises a storage unit which stores therein a document database consisting of a plurality of documents based on a hierarchical structure and a management information database consisting of a information indicating a relation between a document in an upper layer and a document in a lower layer and a plurality of management information including information on a version number of each document. A server is connected to the storage unit and is provided with the manager of the documents. A client is connected via a network to the server and retrieves, by accessing the server, a document in the upper layer and a document in the lower layer each having a specified version number according to the management information.