A safety device for a pre-filled syringe is proposed that comprises a hollow support body with a helical groove formed into an inner surface thereof, a mounting collar for mounting the pre-filled syringe to the support body, a spinning collar with a helical tongue formed to an outer surface thereof and a torsion spring. The helical groove accommodates the helical tongue. Upon release, the torsion spring is capable of exerting a torque upon the spinning collar which causes the spinning collar to rotate within the support body. The engagement of the helical groove and the helical tongue redirects the rotational movement of the spinning collar to a translatory movement that moves the mounting collar in a proximal direction.
