Abstract: For a device for cutting plants with a cutting line (36, 38) which rotates around an axis of rotation and is wound on a reel (13), wherein a slide (16) releasably locks the reel (13) by means of a cam (26) with respect to elements which rotatingly take it along, wherein the length of the free end (37, 39) of the cutting line (36, 38) can be adjusted by unlocking the reel (13), wherein the slide (16) is displaced out of its locked position into its unlocked position by means of centrifugal force in the course of the shortening of the cutting line (36, 38), the cutting line adjustment is simplified and functionally improved in that the slide (16) is maintained in its locked position only by means of the force equilibrium of the mass support forces between its cam (26) and a detent (28) on the reel side, out of which it is displaceable by centrifugal force into its unlocked position, so that the reel (13) can rotate in respect to the cup (12), wherein the cam (26) is returned into the locked position by the mass