In order to extend the life of an artificial hip joint, it is necessary to reduce the amount of UHMWPE cup wear. One of remedies to reduce the wear is to improve surface roughness and roundness of the femoral head. Its surface roughness was successfully improved by ultra-precision finishing by means of abrasive in the previous paper. Furthermore, in order to improve roundness of femoral head, a machining model of the proposed method was developed. In this paper, to improve roundness of a femoral head, a nozzle feed speed planning method is proposed. The feed speed planning can be conducted by feed-forward calculation of machining amount according to the machining model. Nozzle feed speed control experiments showed effective improvement of the roundness, and thus the machining model and feed speed control method were verified to be feasible in practical use.