PURPOSE: To allow the easy implantation of the prosthetic material into the bone of a living body and to additionally improve the fixability of the prosthetic material and the bone of the living body by forming plural curved parts provided on the surface of the implanting part of the body part of materials having elasticity, and providing the curved parts in such a manner that the parts between both ends thereof project outward of the implanting part.

CONSTITUTION: An artificial osteohead 1 has the plural curved parts 2 formed of the materials having elasticity provided in such a manner that the parts between both ends thereof project outward to the surface of a stem 5 on the stem 5 which is the implanting part to the hard tissue. In addition, both ends of the curved parts are fixed to the surface of the stem 5. The femur of a human body usually curves and a clearance arises when a straight bar is inserted thereon. Even if the prosthetic material having the shape complying with the curving shape of the myelocavity is formed, the generation of the clearance between the prosthetic material and the bone of the living body is unavoidable. However, the curved parts 2 formed of the elastic materials to be interposed in this clearance by deformation fix both by having a buffer effect and, therefore, both are more surely fixed over a long period of time.