A method and a device for grinding strand-like fibrous material, wherein the strand-like fibrous material is fed towards the cutting edge of a cutting mechanism and wherein a moveable striking mechanism for grinding the fibrous material cooperates with the cutting mechanism. Associated with the cutting mechanism is a moveable clamping mechanism, by means of which the fibrous material is clamped in an oscillating manner. To produce optimally uniform fibrous shreds, as defined by the position of the cutting edge, the fibrous material is guided through an oscillating clamping gap formed between the clamping mechanism and the cutting mechanism, wherein the clamping mechanism is guided in a back and forth clamping movement relative to the cutting mechanism. For this purpose, the clamping gap is formed by arranging the clamping mechanism and the cutting mechanism opposite one another in a clamping plane.