A management apparatus searches whether or not a notification file corresponding to a document name displayed on a display is present within a difference management table, and displays a predetermined indication "*", which indicates the presence of a notification file, on the display, when a notification file is present. When conventional documents are converted into electronic documents, there arises problems that rather inconveniences would be brought compared to the paper-printed documents before converted into the electronic documents, and these inconveniences may cause mistakes in the work and misjudgments in the maintenance and operation of machinery and equipment and may induce considerable economical loss in the business activities and serious accidents in the maintenance and operation of machinery and equipment. However, these problems are solved by the present invention.