Recent manufacturing industries face various problems caused by the shorter product life cycle, the higher demand for cost and quality, and the more diversified customer needs. In this situation, it is very important to shorten the lead-time of the manufacturing system construction. Therefore, the manufacturing simulation is watched with keen interest. However, it is used only for the design stage of the construction. It is not useful for the implementation stage because of a proprietary simulation language and a complex modeling. This chapter develops a simulation environment that can be used easily throughout the manufacturing system life cycle. The approach is based on a distributed architecture, ORiN and high-level architecture (HLA). This simulation environment is composed of some manufacturing simulators, real FA devices in the factory, and its emulators. By distributing them into one simulation environment on the network, a large-scale simulation and a highly accurate simulation are achieved.