Abstract: A storage stores base model master data including specification data for reference models and for past cases. A searcher in a calculator performs a data search on the base model master data using a requested specification input as a search key. A list creator creates a base model list listing a selected base model and specification data for the base model. The searcher determines whether at least one of the reference models satisfies the requested specification, selects, in response to at least one of the reference models satisfying the requested specification, the at least one reference model and adds the at least one reference model to the base model list, and selects, in response to the reference models dissatisfying the requested specification, a base model satisfying the requested specification from the past cases and adds the base model selected from the past case to the base model list.