The aim of this study was to elucidate the relationship between the surface roughness and osteoconductivity of anodized titanium surfaces. Before anodizing, titanium substrates with different surface roughness were prepared by wet-polishing. These substrates were anodized at various voltages in H₃PO₄, H₂SO₄, and NaOH aqueous solutions, and their surface roughness was controlled simultaneously at the micron level. Surface roughness of these coatings was expressed with the arithmetical means (Ra). The osteoconductivity of anodized samples was evaluated by in vivo tests. In in vivo tests, samples were implanted in rats’ tibia for 14 d. Anatase type TiO₂ films were formed on all of the anodized samples for in vivo tests. It was newly found that TiO₂ film with small Ra value exhibited high osteoconductivity than that with high Ra value, especially when Ra value was <0.3 μm. In addition, the osteoconductivity of anodized samples with Ra/μm >0.3 was not improved by anodizing, showing the same low osteoconductivity of as-polished samples. These tendencies were observed for all of the TiO₂ films regardless of the type of electrolytes.