In an internal fixator having a sliding mechanism for treating femoral trochanteric fracture, it is intended to firmly hold the femoral head by setting a sliding direction at a high angle. The fixator is constituted of a sliding nail, a femoral head nail, and a sleeve plate. The sliding nail is inserted at a high angle of about 160° in relation to a femoral axis. The femoral head nail is inserted at a low angle of about 95°. A tip of the femoral head nail is located within the femoral head. The femoral head nail is combined and joined with the sliding nail within the bone. A sliding nail passes and slides within the sleeve of the sleeve plate. A sliding direction is consistent with a tangential direction of an inner cortical bone at a fracture side. Thus, displacement between the fracture edges is less likely to occur and excessive shortening can be avoided. With the femoral head nail, the femoral head can be firmly held.