A polyaxial bone anchoring device is provided including a bone anchoring element (1)； a receiving part (4,4') for a rod (5)； an insert piece (6,6',6'') that can be mounted to the receiving part (4,4'), having a seat (18) for the head of the bone anchoring element (1) to permit pivoting of the head relative to the seat, wherein the insert piece (6,6',6'') has a bounding edge with an opening (17) that is smaller than that of the head； and wherein the bounding edge permits the bone anchoring element (1) to pivot at a larger angle at a first location of the bounding edge than at another location of the bounding edge； and wherein the insert piece (6,6',6'') is rotatable with respect to the receiving part and wherein the receiving part (4,4') has a first flat surface portion (13) for supporting the insert piece (6,6',6''), which has a second flat surface portion (15a) facing the first flat surface portion (13). Alternatively, interchangeable insert pieces may be provided.
