PURPOSE: To provide the title device of simple mechanism, causing little troubles such as wrappings, capable of debonding webs in high speed, so designed that fibrous webs attached to a differ is ensured to be debonded through the adsorptive power and rotation of a debonding roller.

CONSTITUTION: An air suction range-controlling tube 3 is concentrically penetrated on the inner surface of a debonding roller 2, and an opening 3a is formed over a specified angle range from the contact position P with a doffer 1. Fibrous webs a attached to the surface of the doffer 1 near an intermediate region of the opening 3a are moved from the doffer 1 to the debonding roller 2 through the absorptive power and rotation of said roller 2, and eliminated off the roller 2 at a position out of the suction range, then fed into e.g. a coiler.