To simply mount helical reinforcement, which is used for a reinforced block, with a prescribed pitch in such a manner as to bring it into close contact with main reinforcement.

The helical reinforcement is elongated by utilizing the self- weight of the helical reinforcement and/or that of a supporting frame, which is fixed to the helical reinforcement, and located in a prescribed position with the prescribed pitch, and the turning of the supporting frame makes the diameter of the helical shape of the helical reinforcement larger/smaller for the purpose of bringing the helical reinforcement into close contact with the main reinforcement. In addition, a component for maintaining the pitch is used to increase the accuracy of the pitch of the helical reinforcement, and the helical reinforcement nonuniform in diameter is used to facilitate close contact mounting.