A polyaxial bone anchoring device is provided comprising a bone anchoring element (1) having a shank (2) to be anchored to a bone and a head (3)； a receiving part (5, 5') having a longitudinal axis (C), a channel (54) for receiving a rod (100) and an accommodation space (52, 51) for pivotably holding the head； a pressure member (7, 7', 7", 7"') positioned in the receiving part and configured to exert pressure onto the head to lock the head in the receiving part； wherein the pressure member (7, 7', 7", 7"') comprises a pressure exerting surface (75) and a deformable portion (77, 78； 77', 78'； 77", 78") having a free end (77a, 78a) wherein the deformable portion is configured to assume at least a first configuration and a second configura-tion, a locking member (8, 8', 8", 8"') that is insertable into the channel (54) and that is configured to exert a force onto the deformable portion； wherein when the head (3) and the pressure member (7, 7', 7", 7"') and the locking member (8, 8', 8") are in the receiving part (5, 5'), the free end (77a, 78a) of the deformable portion is supported in the receiving part, and wherein the locking member (8, 8', 8") is movable in the channel along the longitudinal direction in such a manner that it first contacts the deformable portion (77, 78； 77', 78'； 77", 78") and exerts a force onto the deformable portion to bring the deformable portion from the first configuration into the second configuration thereby locking the head, and thereafter the locking member (8, 8', 8") comes into contact with the rod (100) and locks the rod.
