In the present disclosure, an artificial joint stem includes a base and a coating film located on the base. The base includes a first region, a second region, and a third region located in sequence. The coating film contains a calcium phosphate-based material and an antimicrobial material. The coating film is located across the first region and the second region, and the third region is exposed from the coating film. The surface of the coating film located in the first region has a larger surface roughness than the surface of the base in the third region.