Surface charges of biomaterials are recognized as one of the important factors to determine cell and tissue responses. The HA ceramics polarized at various temperatures were estimated by implantation tests. The HA ceramic samples with the polarization treatment at temperature ranging from 250 to 500°C were implanted into bones. These phenomena were observed regard less the polarization temperature. It was obvious that the negatively chargedsurfaces acquired the excellent osteoconductivity at the polarization temperature from 250 to 500°C. The similarity of the tissue reactions implied that the variation of stored charges was within a tolerance of an effective stimulation and that the enhancement mechanism of the osteoconduction had not a linear sensibility of electrostatic charges.