A safety device (20) for shielding a medical needle (25) comprises a needle mount (28) supporting a medical needle and a needle shielding sleeve (34) arranged coaxially with the mount for sliding movement from an initial needle shielding position to a non-shielding position whereat at least the tip of the needle is exposed beyond the sleeve. Either the sleeve (34) or the mount (28) has both an abutment surface (31) and a sliding surface (29). A flexible connection mounts a radially deformable resilient finger (37) on the other of the sleeve and mount so that a first finger part (46) is configured for radial alignment with the abutment surface (31) where the finger blocks movement of the sleeve or for radial alignment with the sliding surface. A control member (40) is slidable coaxially with the sleeve and is co-operable with a second finger part (47) to the other side of said flexible connection. The control member (40) has a set position at which the first finger part is in radial alignment with the sliding surface so allowing movement of the sleeve from its initial shielding position towards its non-shielding position. This causes deformation of the finger which urges the sleeve back to a shielding position. The movement of the sleeve also causes the control member to be displaced from the set position. This movement of the control member (40) drives the second finger part outwardly which urges the first finger part inwardly and so into radial alignment with the abutment surface following the return of the sleeve to a shielding position. Subsequent movement of the sleeve is blocked by the finger engaging the abutment surface.Le dispositif de sécurité (20) ci-décrit, destiné à protéger une aiguille médicale (25), comprend un montage aiguille (28) supportant une aiguille médicale et un manchon de protection daiguille (34) disposé coaxialement sur ledit montage pour permettre le déplacement par coulissement dune position de protection daiguille initiale à une positio
