The medical gases used in a hospital are life-supporting element that gives direct influence in maintaining the life of a patient. Therefore, at the sections where the medical gases are used, the medical gas must be clean, highly pure and supplied under stable pressure. Our medical gas system has our strict company standard. The system has a thoroughgoing color coordination according to the kind of gas, an audio-visual monitoring system capable of checking the situation, and a device to prevent cross connection at medical gas outlet based on the concept, "more safely" and "more securely".