According to the invention, a safety device (1) for a pre-filled syringe (2) comprises a hollow support body (1.2) to retain the pre-filled syringe (2) therein, a hollow needle shield (1.1) that is slidable relative to the support body (1.2) and guiding means for guiding the movement of the needle shield (1.1) relative to the support body (1.2). The guiding means comprise a guide pin (1.1.2), a guide track (1.2.4) and a cut-out (1.2.5) adjacent to the guide track (1.2.4). The guide pin (1.1.2) protrudes into the guide track (1.2.4) and moves within and along the guide track (1.2.4) when the needle shield (1.1) is slid relative to the support body (1.2). The cut-out (1.2.5) allows a side wall (1.2.6) of the guide track (1.2.4) to be deflected in a lateral direction (L) perpendicular to a central axis (A) of the safety device (1).
