Mechanical design requires high-experience knowledge, and an expert system is effective in such a situation. In case knowledge is inputted into this expert system, it is desirable for an expert to directly input knowledge. In this research, a system to which the knowledge input to an expert system is made as for anyone is proposed. Therefore, an expert system structure is described first, and the knowledge base built by the production system is described berow. The Expert system is made as an experiment by them, and the mechanical design expert system and knowledge base has validity checked.