To solve a problem that CRT display data and event data outputted from a controller for controlling processes are not effectively utilized.

Information such as event information extracted from the controller for controlling a plant is stored for a fixed period, each problem of the plant and its countermeasure are estimated from the stored information and data from a database and the estimated problem and measures are stored in the database. Since the past problems and their measures are arranged and stored in the data base, the countermeasures of each problem can quickly be found. The problems and countermeasures are sorted into plural patterns by the ratio of the number of operation tags to the number of control tags outputted from the controller and the ratio of the number of alarm messages to the total number of tags and the problems of the plant and their countermeasures are patterned by the sorted patterns. Thus each problem and its countermeasure can be estimated by simple processing.