To provide a safety-ensuring method considering safety of a work on a roof, such as an installation work of a solar panel, and to provide a mounting tool for safety measures used for the method.

The safety-ensuring method adapts a method as follows. After the mounting tool 10 for safety measures provided with a mounting part 30 to which a main rope or a life rope is attached is fixed at a first position 41 in the vicinity of eaves of a roof, the mounting tool 10 for safety measures and a worker are tied by a first life rope, and in this state, another mounting tool 10 for safety measures is fixed at a second position 42 in the vicinity of the roof R. Then, after the mounting tool 10 for safety measures at the second position 42 and the worker are tied by a second life rope, the first life rope is removed from the mounting tool 10 for safety measures at the first position 41 or the worker. The mounting tools 10 for safety measures are fixed at a plurality of positions while moving horizontally in the vicinity of a ridge from the second position, and a main rope W is stretched among the mounting tools 10 for safety measures located in the vicinity of the ridge.