Abstract: A storage apparatus stores existing data including data relating to management of an instrument and data on actual records of the instrument, information on path structure of the existing data, mission information relating to a task in the facility operation, and information on the path structure of the mission information. An arithmetic operation apparatus extracts information on data meanings of terms contained in the existing data based on the existing data and the path structure of the existing data, and generates information of the degree of association between the plurality of terms. The arithmetic operation apparatus generates mission management information based on mission information, the path structure of the mission information, and the information on the degree of association between the terms, the mission management information including information on a meaning of each of a plurality of tasks relating to facility operation and chronological information on the plurality of tasks.