Abstract: An external bone distractor (1) having a threaded curvilinear rod (4) including several diametrical flat sections (7,8) with the thread (9) of the rod (4) continuing along longitudinal lines. At least a pair of carriages (2) are engaged on the rod and solidly connected to spindle supports (3). Guide members (10, 13) cooperate with the flat sections for preventing rotation of each of the carriages about the axis of the rod. Adjusting devices (14, 15) position each of the carriages along the length of the rod. The curvilinear rod (4) provides for use of the distractor in reconstruction of curved bone segments, such as in the jaw, face and skull.