PURPOSE: To demount a long material wound on a spool easily from the spool.

CONSTITUTION: When a wire member 14 after working is demounted from a spool, a lock nut 13 is demounted from a driving shaft 10 at first, and then also a demountable frame 3 is demounted from the driving shaft 10. When a slide bearing 8 is shifted slightly leftward, each link bar 7 tilts from a vertical state, and each movable curved plate 5 turns, having the point installed in a turnable manner on a link holder 6, as fulcrum. Accordingly, six movable curved plates 5 tilt to a tapered state (shrinked state towards the side for demounting the wire member 14 after working) from a horizontal state (perpendicular state for the frame). The inclination limit of each movable curved plate 5 is regulated by the contact of each link bar 7 with a stopper 9. Accordingly, the wire member 14 after working which is wound on the peripheries of six movable curved plates 5 can be easily demounted from the spool.