A transplant material which is capable of imparting desired mechanical properties, elevating bone tissue repair speed and improving biocompatibility. This transplant material comprises an artificial and biologically inactive material, which is to be implanted in vivo as a substitute for bone tissue, and at least one type of cells selected from among osteoblasts and precursory osteoblasts which are adhered to the surface of the artificial material so that the artificial material is coated with the bone matrix produced by the cells. The artificial material involves not only a biologically inactive material but also a biologically inactive material coated with a biologically active substrate. This transplant material is produced by culturing mesenchymal stem cells collected from a living body to differentiate into at least one type of cells selected from among osteoblasts and precursory osteoblasts and then culturing the cells together with the artificial material to thereby adhere the differentiated cells on the surface of the artificial material and coat the surface of the artificial material with the bone matrix produced by the differentiated cells.