PURPOSE: To assuredly hold a bead from the inner side in the radial direction even when a thickness of a band member is thick as a whole or partially.

CONSTITUTION: Firstly, only bead lock bodies 41 and 42 synchronize. Thereafter, sleeve bodies 37 and 38 are hooked by the bead lock bodies 41 and 42 and moved with them to the outer side in the radial direction so as to hold a bead D from the inner side in the radial direction. At this time, the bead lock bodies 41 and 42 protrude to the outer side in the radial direction from the sleeve bodies 37 and 38 protruding from sliders 29 and 30 to the outer side in the radial direction, so that the maximum stroke becomes longer and holding becomes certain.