To solve the problem that an object-oriented language makes it easy to structure classes, methods, etc., but naming is not clear and hard to use and that an ordinary person except an expert cannot develop a program with ease because the knowledge of the program language is needed.

A method of ontological engineering making it easy to develop a program by using the framing of natural languages is adopted to structure the framing of basic ontology with provided classes, etc., of the object-oriented language. Further, the hierarchical structure of ontology for managing the ontology is structured. Furthermore, a mechanism which can easily develop a program that an ordinary person easily reads by employing sentence patterns of natural languages is structured as an execution mechanism.