A femur fixation apparatus includes an intramedullary nail, a lag screw that is inserted through the intramedullary nail, and an adjuster 4 fitted in the intramedullary nail. The adjuster includes a sliding part unrotatable and slid-movable in a longitudinal direction relative to the intramedullary nail and a rotation part rotatably connected to the sliding part. A lower end of the rotation part is formed with an inward flange part and a cutout. An engaging part of an engaging protrusion formed to the sliding part is inserted into the rotation part via the cutout from the radial direction, and the engaging part is supported by the inward flange part from the bottom, rotatably connecting the sliding part to the rotation part.