Tunnels have been constructed in various places for transportation and lifelines. During tunnel construction, the industrial accidents have occurred due to falling rocks from the tunnel face. A large amount of falling rocks is confirmed in the precursor of tunnel collapse. Therefore, it is necessary to detect falling rocks to prevent industrial accidents and to grasp of the situation on tunnel face. As conventional methods, the inter-frame difference method and the laser measurement method were proposed. However, those methods were difficult to monitor the entire tunnel face and detected moving objects other than falling rocks. In this paper, we propose a falling rocks detection method that combines the moving object detection method on the tunnel face and the estimation method of excavation points using single color markers. It was confirmed that only falling rocks were detected during excavation experiment.