The invention relates to an osteosynthesis device having a bone screw (12), which has a threaded shaft (24) and a ball head (26), and having a fork head (14), which has a groove (32) and two legs (34), the ball head (26) being pivotably supported in the fork head (14), and having a pressure piece (16), which is seated on the ball head (26), the pressure piece (16) being braced on the fork head (14) and having two lateral fins (48) extending in the axial direction (30) of the fork head (14) and away from the threaded shaft (24) it is proposed that the pressure piece (16) is supported in the fork head (14) with prestressing in the axial direction (30) and thus in the direction toward the ball head (26) in that at least one of the fins (48) is slit transversely to the axial direction (30) of the fork head (14), so that a slit (50) forms a spring tongue (52), and the pressure piece (16) is thereby resiliently embodied and is braced via the spring tongue (52) on the fork head (14), and that a protrusion (70) protrudes in the axial direction (30) into the slit (50) and that the protrusion (70), for limiting deformation or deflection of the spring tongue (52), forms a stop (72), acting in the axial direction (30), for the spring tongue (52).
