This set comprises an intervertebral implant (2) for immobilising a vertebra (100) with respect to another and an instrument (3) for installing this implant； the implant (2) comprises a longitudinal end designed to be connected to the instrument (3), and the instrument (3) comprises a rod (26) having a free distal end (28), wherein the implant (2) is designed to be removably mounted. According to the invention: &mdash；said free distal end (28) of the instrument rod (26) is rounded； &mdash；the instrument (3) comprises releasable means (22) adapted, in a position, to retain the flexible strands (6a, 6b) in strain on each side of said rod (26), according to equivalent strains, and, in another position, to fully free these strands (6a, 6b)； and&mdash；the means for mounting the implant (2) on said distal end (28) are constituted by the two flexible strands (6a, 6b) held in strain by said releasable means (22), this retaining in strain allowing to achieve mounting of the implant (2) on this distal end (28), while retaining this distal end (28) engaged in a cavity (15) of the implant (2).
