In this study, we aimed to combine good mechanical properties of bearing grade PEEK with bioactivity for more attractive implant material. We succeeded in providing bioactivity for bearing grade PEEK by the following three steps. First, we formed micropores on bearing grade PEEK by the immersion in sulfuric acid. Second, the bearing grade PEEK plate with micropores was exposed to O₂ plasma by glow discharge for providing hidrophilicity. Finally, Apatite Nuclei (AN), precursors of hydroxyapatite (HAp), was deposited on the substrate. This bioactive bearing grade PEEK was covered with HAp within 1 d immersion in SBF. It was suggested that AN were essential for providing bioactivity to bearing grade PEEK in the present method. The adhesive strength between induced HAp layer and bearing grade PEEK was obtained due to mechanical interlocking effect of micropores formed by sulfuric acid treatment. In addition, it was suggested that the combination of sulfuric acid treatment and subsequent glow discharge treatment was effective for good adhesive strength between induced HAp layer and bearing grade PEEK plate.