The safety carabiner includes a body including a central portion extended at the ends thereof by a first hook-shaped branch provided with a retaining portion and a second branch, respectively, the first branch having a retaining portion, and a closing finger pivotably mounted on the second branch of the body around a pivot axis, between closed and open positions of the carabiner; where retaining portion includes a slender end portion that is generally tapered seen from the side and the retaining portion is configured so that, when the carabiner extends substantially perpendicular to said flat support, and the first and second branches of the carabiner are bearing on said flat support, the free end of the end portion forms the bearing zone of the first branch on said flat support.