PURPOSE: To shorten a time in which a distance between side plates is matched with the width of a metallic band to be wound by arranging side plates so that separators for guiding a metallic belt pressed against and locked to the outer peripheral surface of an air shaft through expansion of the air shaft are positioned facing a winding main shaft through a wound metallic beltlike material.

CONSTITUTION: When a distance between side plates 2 is varied and fixed so as to match with the width of a metallic belt 1, a part of a shaft diameter is first reduced through reduction of the air pressure of an air shaft 5, and a gap is provided between the outer periphery of the shaft and the inner periphery of the side plate 2 to move the side plate 2. Secondly, after a distance between the side plates 2 is matched with the width of the metallic belt l intended to be wound, the air pressure of the air shaft 5 is increased again to increase a shaft size, and the outer periphery of the shaft and the inner periphery of the side plate 2 are locked to each other for fixing. Namely, since the side plates 2 are easily moved and can be simply fixed in an arbitrary position, a spacer can be eliminated, and a time in which a distance between the side plates 2 is adjusted can be shortened.