Research on realization of virtual factory It is necessary to examine what production activity to become to achieve an efficient production activity beforehand enough, and plan as detailed a production plan as possible. However, because information on various restrictions of the factory etc. which should be considered becomes huge to plan the production plan, complex information processing is demanded by those who plan. Then, we thinks the production activity of the factory is executed virtual in the computer, the problem etc. of the production activity are found in the sight, and the factory simulator which can plan the best production plan is constructed. An equivalent factory model (virtual factory) to an actual factory is defined in the computer, and the construction of the system which can freely execute the simulation is researched.