PURPOSE: To bundle by using a bundling belt which can repetitively be used, untie a bundle easily and automate untying easily.

CONSTITUTION: Following steps are taken in untying a bundle which has been made by winding a bundling belt 2 around a load and engagedly attaching both ends of the belt with an engaging tape 3 comprising a pair of tapes 3a, 3b which can be freely attached and peeled. A position of a ring-like hooking metal 4 rotatably provided at an end of the bundling belt 2 is detected by a metal position detecting sensor, and also the hooking metal 4 is made to stand perpendicularly by magnetic force of a magnet 6. Then a hook 7 is hooked in the hooking metal 4, the hook 7 is horizontally moved to pull an end of the bundling belt 2 horizontally, and engagement of the pair of tapes 3a, 3b of the engaging tape 3 is disengaged.