Lean production system is a production concept developed by Toyota. The implementation of lean makes Toyota quickly became one of top 10 companies in the world after World War II and then achieved the largest carmaker in 2007. Through observing in Gemba for years, Toyota developed a methodology to evaluate all production processes from suppliers to customers, called value stream map. An ideal value stream is a lean production which is required to achieve just-in-time manufacturing and not to produce unnecessary or flawed stuffs in any production process. Thus, lean production system can fits to the demand of mass customization. Therefore, some companies in manufacturing, healthcare industry and service industry in Taiwan also starts introducing the concept of lean production into their management system. It is worth noting that nowadays, under Industry 4.0, many companies expect to build automatic and intelligent production lines. However, an automatic and intelligent production line without a good value stream should produce more waste and then cost the company much more than before. The content of this course includes the basic concept and methodology of lean production system，the process of introducing lean production system into a production line，and the case study. Meanwhile，the concepts of project management and accounting related knowledge are also introduced to control the performance and progress of lean improvement.