PURPOSE: To detect the abrasion of a clutch disk accurately without requiring the time and the labor of regulating, even though there is an error in the distance to detect owing to the accuracy of a part and the like.

CONSTITUTION: A clutch is cut off by bending a clutch spring 3 by sliding a release bearing 9 in the axial direction according to the operating amount. In a clutch cutoff device to inform the abrasion limit of a clutch disk by detecting the displacement of the release bearing 9, a displacement sensor 15A to detect the displacement of a nonrotary member (a bearing holder 8) of the release shaft 9 is provided to an unmoved member (an outer tube 6) at a clutch housing 2 side, and furthermore, the movable detector is linked to the displacement in the axial direction of the nonrotary member (the bearing holder 8).