An artificial joint apparatus used as an artificial joint inserted into a
bone is provided. The artificial joint apparatus includes: a body having
a stem having a shape substantially corresponding to a space within the
bone, into which the stem is inserted, and a head formed integrally with
the stem; and a jacket made of a plastic material and surrounding an
outer surface of the stem of the body. The jacket is constructed with an
outer layer containing a bone-friendly material and an inner layer mainly
made of a plastic material. Since the plastic jacket of an artificial
joint apparatus has a bone-friendly material, it is possible to promote a
growth of a bone contacted thereto. In addition, the bone is grown into a
space where the bone-friendly material is dissolved, so that the jacket
and the bone can be securely adhered. Since the bone-friendly material
also exists in an inner portion of the jacket it is possible to
continuously accelerate a bone in-growth.