Organic polymer coated with hydroxyapatite (so-called apatite) on its surface is a candidate of new hybrid materials for medical applications since it is expected to show bone-bonding ability and achieve mechanical properties derived from organic substrate. We have shown that some kinds of polyamide films containing carboxyl group or sulfonic group form hydroxyapatite in the simulated body environment, when they are incorporated with calcium chloride. In the present study, the polyamide containing carboxyl groups were modified with silanol groups and its apatite-forming ability was investigated in 1.5SBF, which has ion concentrations 1.5 times those of a simulated body fluid (SBF). It was found that polyamide films modified with silanol groups showed higher ability to induce apatite on its surface in 1.5SBF than the films without the modification, when they were incorporated with calcium chloride.