The invention relates to a mechanical device intended for correcting a malformation of the bones of the body. The device is continuously adjustable, making the surgeons work easier and reducing surgery time, thus reducing the risk of infection and, above all, guaranteeing the desired precision for surgery. The device comprises a top plate (1) suitable for sliding over a bottom plate (2) by means of a guide (7). Said plates can be screwed on either side of an angled notch made in the bone. The plates comprise respectively top (5) and bottom (6) bearings of the notch of the bone. Said bearings form an acute-angle bevel which substantially matches the surfaces of the notch. One of the plates is provided with an adjustment screw (4) for continuous adjustment of the relative positions of the plates. The device also comprises a locking screw (3) suitable for maintaining the open position of the device and, consequently, the final angle of the notch of the bone in the desired position. The Top bearing of the notch of the bone having angular adjustment is suitable for correcting the angle of the bevelled surface of the bearing, in particular the tibial slope, by means of a tapered screw (8) adjustment an angular space in the bearing.