PURPOSE: To improve the recognizability for singular data and to utilize individual data effectively by applying a diagnostic rule to respective data in a data base, extracting data on a judgment of facility abnormality, and making a display method for entry values in a data display format distinctive from others.

CONSTITUTION: A facility diagnostic part 2 takes a diagnosis according to data in the data base 3 and displays the diagnostic result at a diagnostic result display part 5. The data are classified into factor data when a deterioration state is indicated by the diagnostic result according to a data decision rule stored in the facility diagnostic part 2 and they are re-inputted as process data to the data base 3. Further, the data are displayed on the data update operation screen of a data editing part 1, for example, in blue when exceeding a permissible JIS thickness reduction quantity, in red when exceeding a minimum necessary thickness reduction quantity, and in white when less than the permissible thickness reduction quantity.