A polyaxial bone anchoring device includes a receiving part having a longitudinal axis, a channel for receiving a rod, and an accommodation space for pivotably holding a head of a bone anchoring element, and a pressure member configured to be positioned in the receiving part and to exert pressure onto the head to lock the head in the receiving part. The pressure member includes a pressure exerting surface and a deformable portion having a free end, wherein the deformable portion is configured to assume at least a first configuration and a second configuration. The polyaxial bone anchoring device further includes a locking member configured to be inserted into the channel and to exert a force onto the deformable portion. When the head and the pressure member and the locking member are in the receiving part, the free end of the deformable portion is supported in the receiving part, and the locking member is movable in the channel along the longitudinal direction in such a manner that the locking member first contacts the deformable portion 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. Thereafter the locking member comes into contact with the rod and locks the rod.
