A device for increasing safety in conjunction with removal of a cannula from an injection body of a syringe, the device comprising: - a tube having a group of parallel longitudinal slots consisting of two diametrically disposed pairs of parallel slots (11A, 11B, 16A, 16B), wherein a flexible strip is defined between each of two pairs of adjacent slots of the group of parallel longitudinal slots (11A, 11B, 16A, 16B); - a casing mounted on the tube and provided with two internal recesses extending in a longitudinal direction of the casing, wherein the casing has a variable wall thickness in circumferential direction; and - a holding component that is operable to receive the casing along with the tube, wherein during downward displacement of the casing and the tube the casing comes to rest against an internal first stop surface of the holding component and during further downward displacement, the lower end of the tube comes to rest against another stop surface of the holding component; wherein the cannula is removable from the syringe by a cannula removing separation mechanism, characterized in that the tube and the casing are operable to rotate around a common longitudinally running central axis such that thicker wall parts of the casing come to be located directly in front of the flexible strip in the tube and exert a clamping action on the flexible strip for removal of the cannula from the syringe, wherein the clamping action presses an internal heel located on the inside of the flexible strip of the tube into a track going round the front end of the injection body in the injection body, thus providing clamping of the tube relative to the injection body. - a tube having a group of parallel longitudinal slots consisting of two diametrically disposed pairs of parallel slots (11A, 11B, 16A, 16B), wherein a flexible strip is defined between each of two pairs of adjacent slots of the group of parallel longitudinal slots (11A, 11B, 16A, 16B); - a casing mounted on the tube and provided with two internal recesses extending in a longitudinal direction of the casing, wherein the casing has a variable wall thickness in circumferential direction; and - a holding component that is operable to receive the casing along with the tube, wherein during downward displacement of the casing and the tube the casing comes to rest against an internal first stop surface of the holding component and during further downward displacement, the lower end of the tube comes to rest against another stop surface of the holding component; wherein the cannula is removable from the syringe by a cannula removing separation mechanism, characterized in that the tube and the casing are operable to rotate around a common longitudinally running central axis such that thicker wall parts of the casing come to be located directly in front of the flexible strip in the tube and exert a clamping action on the flexible strip for removal of the cannula from the syringe, wherein the clamping action presses an internal heel located on the inside of the flexible strip of the tube into a track going round the front end of the injection body in the injection body, thus providing clamping of the tube relative to the injection body.