An intramedullary bar (11) is so formed in a bar shape as to be inserted along the bone marrow at the distal portion (100b) and has a first through hole (18) formed through the side surfaces. A sleeve (12) is formed in a tubular body, inserted into the first through hole (18), and has a second through hole (23) formed therethrough along the longitudinal direction of the cylindrical body. A lag-screw (13) is so formed in a bar shape as to be inserted into the second through hole (23) and has a screw part (24) screwed into the proximal portion (100a) at the end. An angle adjusting means is formed in the first through hole (18) and the sleeve (12) and capable of changing the tilt angle of the lag-screw (13) to the intramedullary bar (11). Consequently, this device can be adapted to any of various lag-screw fitting angle required depending on the situation of operation, can eliminate the restriction that a large number of intramedullary bars matching different lag-screw fitting angles must be prepared for operations, and can also eliminate the re-insertion of the intramedullary bar during an operation.
