PURPOSE: To prevent occurrence creasing, folding, meandering and slipping and to facilitate the extraction of a spool by providing a two stage shaft expanding mechanism which in combination of a shaft expanding mechanism given by displacement control of a taper segment and a shaft expanding mechanism given by force control using a fluid expanded tube.

CONSTITUTION: Until a parallel part 22 on the front end side of an expandable segment 1 strikes upon a parallel part 21 of a stationary taper segment 2, and a parallel part 23 of a sleeve 3 strikes upon a parallel part on the rear end side of an expandable segment 7, a carriage 10 is moved along a railway by an air cylinder. Accordingly, their rotational axes are aligned with each other, and taper parts 19a, 19b of the expandable segment ride on taper parts 20, 24 of the stationary segment 2 so that expansion is made by a predetermined value. Further, after completion of initial winding, compressed air is fed into a rubber tube 4 through a rotary joint 5 so as to press the rubber tube 4 against the expandable segment 1. Accordingly, the expandable segment 1 is pressed against the inner peripheral surface of a material 17 to be wound up. Thereby it is possible to wind up the material without meandering, slipping or the like.