To easily control cross sectional deformation of a weight with a high degree of freedom for changing weight while fixation of a heavy weight being made possible without increasing a load in case of caulking.

A weight 5 to be installed round the outer circumference at the lower end of a tube 4 made up of a soft elastic bendable material is formed of a wound wire, and a part of the wound wire is pressed against and fixed to the tube 4. The diameter of wind at the pressed part 5a is in a shape corresponding to the diameter of the tube, and the diameter of wind at a non-pressed part 5b is larger than the diameter of the tube and should be determined to be the diameter materializing a required weight. With the pressed part 5a formed of a thin wire in loose winding while the non-pressed part 5b being formed of a thick wire in tight winding, the wire can be pressed against the tube 4 with a lesser load.