A device (17) is provided for tensioning a flexible band (3) used to maintain a bone element on an implant. The device includes a rod (18) having a first end (19) provided with means (20) for bearing on the implant, a movable part (32) for hooking the flexible band onto a portion (28) of the device, and means (34) for adjustably locking the movable part in translation in relation to the portion of the device. The rod (18) includes a gripping handle (26) at the second end (27) thereof. The aforementioned portion of the device forms an angle &alpha； with the rod (18) to which it is rigidly connected at an intermediary point, the direction of the band being altered at an angle, and the aforementioned adjustable locking means (34) includes manual screwing means (35) for actuating the movable part.
