This invention provides cement-less type artificial joint stems with the use of complex material which can be connected to bone without using cement, does not get loose over a long period of time, has excellent durability, and has appropriate external form and stiffness to meet the condition of each patient. Stem 1 with the use of composite material inserted in the insertion hole 8 which is penetrated into the bone 7 and fixed to the bone 7 without using cement, has the external form of the epiphysis which fits the internal form of the insertion hole 8, has the main part 3 with changing stiffness so that in the neighborhood of the boundary between the epiphysis and diaphysis, stiffness becomes lower as approaching toward the diaphysis, and possesses a neck part 2 to place a spherical head in an artificial joint provided at the proximal end of the main part.