This insertion and locking device (1) for an implant in a long bone comprises an elongate body (2) designed to be received in a medullary canal of the long bone, the body defining, in a first position called the insertion position, a first transverse size and, in a second position called the locking position, a second transverse size greater than the first transverse size. This device furthermore comprises drive mechanism (8) suited to enable the body (2) to move from the first position to the second position. In addition, the elongate body (2) comprises a central member (3) defining a main axis and at least one locking member (6) defining at least one axis of movement distinct from the main axis, the or each locking member (6) being suited to anchoring itself in the long bone under the effect of the drive mechanism.