A control method analysis unit acquires a correspondence relation between signs and model numbers from an apparatus table of an instrumentation diagram, and acquires signs and apparatus symbols, and connection relation among apparatuses, from a drawing of the instrumentation diagram. Subsequently, the control method analysis unit acquires an apparatus classification drawn on the diagram by searching an instrumentation apparatus classification database based on the model numbers, and decides a temperature control method employed by an instrumentation indicated in the instrumentation diagram, from the apparatus classification and the connection relation. The control method analysis unit then links the decided temperature control method to the instrumentation diagram accumulated in a case database. A search processing unit extracts a corresponding instrumentation diagram by searching the case database based on a temperature control method designated as a search condition.