PURPOSE: To automate fixing work for boots, improve the certainty of fixing conditions, and stability.

CONSTITUTION: The outer diameter of each fastening jig 7 is formed as a taper surface 7a which adapts to the taper surface 6b of a taper sleeve 6, and its inner diameter is formed as an inner tooth mold shaped push-pressed part 7b which adapts to a fixing part 1a. When the taper sleeve 6 is moved to axial direction left side, the taper surface 6b is brought in contact with the taper surface 7a, so that each fastening jig 7 is pushed by the taper sleeve 6 to move to an inner diameter side, and the band 3 of the fixing part 1a is pushpressed from outer diameter radiating direction. The band 3 is pressed to the inner diameter side by the tooth mold 7b1 of the pushpressing part 7b, and it is plastically deformed along the shape of the tooth mold 7b1 so as to contract its diameter.