Oral cancer, especially that originates in the maxillary tuberosity, buccal mucosa, and maxillary alveolus, is apt to invade the pterygopalatine fossa, where an intraoral approach is nearly impossible. There are 2 main types of extraoral approach to the pterygopalatine fossa; the anterior approach and the lateral approach. Although the lateral approach has an advantage compared with the anterior approach in terms of cosmetics, after the operation numbness of the lower lip occurs due to the sacrifice of the mental nerve. In the conventional lateral approach, a vertical incision is made in the center of the lower lip; a lateral flap is then elevated with the sacrifice of the mental nerve. The authors introduce here a new lateral approach to the pterygopalatine fossa with preservation of the mental nerve. In the present technique, a vertical incision was made in the corner of the mouth, and a lateral flap was then elevated with preservation of the mental nerve. This technique could also preserve the marginal mandibular branch of facial nerve in patients without a large metastasis in the submandibular lymph nodes. Additionally, expedient mandibular osteotomy, which is applied in the conventional lateral approach, could be omitted in the present technique, thus helping to prevent postoperative infection. The present approach was applied to 5 patients with oral cancer invading the pterygopalatine fossa. The postoperative numbness of the lower lip was estimated using the current perception threshold. The lesions were successfully resected with little numbness of the lower lip, and no postoperative infection occurred in any of the patients. This technique is available as an approach to the pterygopalatine fossa that preserves the mental nerve and can prevent postoperative infection.