A stem (3) includes: a body section (10) which is inserted into a narrowing hole (Ha) formed in a femur (H) and osseointegrated； a neck section (20) which is joined to a tip of the body section (10) and protrudes from the narrowing hole (Ha) to transmit a load from an acetabular side to the body section (10)； and a leg section (25) which is joined to a distal end of the body section (10) to hold a posture of the body section (10), wherein the neck section (20) and the leg section (25) are made of a biocompatible resin, and the body section (10) is made of a biocompatible metal, a biocompatible ceramic, or a biocompatible resin.
