The reduction of operating costs and the increase in efficiency of the manufacturing site are the key to the business competition and increasing revenue. Therefore, the level of manufacturing site management will directly affect the quality, cost, delivery, security, and even production line colleagues morale. This study based on the manufacturing site explores both the management issues faced by the middle manager of the factory in the field management work and its improvement actions. Using the action research method, this study explores how the middle manager is committed to making an analysis and the improvement of the manufacturing site problem under limited resources. The study finds that middle manager strengthens their cohesion and improves the performance and the atmosphere in the workplace through a two-stage improvement effort.