After mandibulectomy in cancer surgery, reconstruction is often performed with a reconstruction plate covered with a soft-tissue free flap in patients in poor condition. However, the rate of complications for mandibular reconstruction is higher with a reconstruction plate than with vascularized bone grafts. We have developed a costal cartilage wrapping method to prevent exposure of the mandible reconstruction plate. The eighth costal cartilage was removed and split into 2 pieces to wrap around the reconstruction plate. In our case, the artificial plate wrapped with costal cartilage graft was not exposed and the skin over the plate did not become atrophic over 27 months follow-up even after irradiation. Wrapping around an artificial reconstruction plate with autologous costal cartilage grafts may be more effective than using only a flap covering to prevent exposure of the plate after tumor ablation and radiation therapy.