Abstract: The invention relates to a stone breaker having a frame supporting the work-table, having a support which is height-adjustable via setting means at its outer ends and is supported by the frame, and having knife-type blades extending parallel to the support, of which blades the counter-blade is supported by the frame and the other, in contrast to the support, is movable towards the counter-blade by means of a lever device, two eccentric drives with eccentric wheels being actuated by the lever device, both eccentric wheels having an outer toothed wheel rim and both outer toothed wheel rims being connected to each other via a movable rack.