A bone anchoring device is provided including an anchoring element (1) having a shaft (2) for anchoring in the bone and a head (3), a receiving part (5) having a top end (5a) and a bottom end (5b), a channel (11) for receiving the rod (6) near the top end and an accomodation space (9a, 9b) for accomodating the head near the bottom end, the accommodation space having an opening (10) towards the bottom end , the opening being sized so as to allow the introduction of the head (3) from the bottom end a pressure element (8) formed in one piece, the pressure element being located at least partly in the accomodation space and having a flexible portion (85) to clamp the head wherein the anchoring element is pivotable with respect to the receiving part and can be fixed at an angle by moving the pressure element inside the accomodation space such that the head (3) is locked within the flexible portion (85) of the pressure element wherein the pressure element comprises a first securing portion (83) which is coupled to a second securing portion (9d) at the receiving part when the pressure element is inserted into the receiving part to prevent loss of the pressure element from the receiving part.
