PURPOSE: To improve a working property by constituting the extent of tensile strength of a tubular braiding fiber body, a collecting strict consisting of a fine line, to be larger than that of a bar material.

CONSTITUTION: A collecting string 2 consisting of plural pieces of fine lines of an Alamide fiber is knitted into a hollow braiding form, forming a holddown member 1 of a tubular braiding fiber body. Then, this holddown member 1 is fitted in an end 8 of a bar material 6, an end 3a of the holddown member 1 is fastened by a stopper 9 of a wire or the like, and the other end 3b is connected to a winch via a pulley 10. Next, this winch is operated and the holddown member 1 is clamped to the bar material 6, and the bar material 6 is tensed with tension imposed. With this constitution, a working property is well improbable.