Abstract: A bone fixing device is disclosed in which a single rod member is arranged in a longitudinal direction of a bone, and at least two block members are mounted on the rod member so that the block members may be fixed to any desired positions in the axial direction and around the axis of the rod member. Pin holding mechanisms for holding a plurality of pins to be inserted into the bone are mounted on the block members, respectively. By the pin holding mechanisms, the pins are positionally adjustable around axes in the first and second directions which are preferably perpendicular to the axial direction. Also, an actuator is fixed to the rod member. One of the block members slidable relative to the rod member is moved in the axial direction relative to the rod member to thereby impart elongation/contraction force to the bone. A detector is fixed to the other member and is brought into contact with a contact located at an end of the rod member to thereby detect the repulsive force from the bone.