To obtain a device of tying a boot end of an elastic body which is capable of reducing labor and equalizing quality by automation of winding and tying of a cylindrical rubber boot end fitted to a case with a steel wire.

A steel wire 11 is relieved by reverse rotation of a roller 13 with holding the end part of 11a of the steel wire 11 by a plucking metal tool 19 while the steel wire which is fed by the roller 13 and is guided by a nozzle 14 winds the boot end 6a with a guide metal part 8, and the plucking metal tool 19 and the guide metal part 8 are released from the steel wire 11 by cutting of a part of steel wire 11 positioned forward of the nozzle with a cutter 22 while a pinching metal tool 21 clamps a crossing part 11b of the steel wire 11, and then the boot end 6a is wound with the steel wire 11 by drawing of the pinching metal tool 21 in the direction of separation with a predetermined force, and both ends of the steel wire are twisted to each other and fixed by rotation of the pinching metal tool 21.