The shaft (duct) is opened at two points, the first shaft (47 meters deep) is found at 1,695 m from the tunnel entrance on the Otsu side and the second shaft (20 meters deep) is located at 2,136 m from the entrance.
竪坑（ダクトスペース）が2か所にあり、大津側の坑口（トンネル入口）から1,695mの位置に第1シャフト（深さ47m）、2,136mの位置に第2シャフト（深さ20m）がある。