Abstract: A bone adjuster 20 has a first lift plate 22 to be fastened to one of two opposed bone fragments to be adjusted, a second lift plate 24 to be fastened to the other bone fragment and an adjusting shaft 26 which is extended between both the lift plates 22 and 24 to adjust a space between the fragments. The first lift plate 22 comprises a mounting plate 28 and a screw-in connecting portion 34 which is connected with the mounting plate 28 via a hinge 36 and in which the adjusting shaft 26 is screwed to be supported. The second lift plate 24 also comprises a mounting plate 42 and a catching portion 48 which is rotatably fixed to the mounting plate 42 via a hinge 46 to catch the leading end of the adjusting shaft 26.