We herein report a case of squamous cell carcinoma of the buccal mucosa with N3 cervical lymph node metastasis in a 63-year-old man. The patient was treated with combination therapy comprising radiotherapy (2 Gy/day, total of 70 Gy), superselective intra-arterial chemotherapy via a superficial temporal artery (docetaxel, total of 70 mg/m2 and cisplatin, total of 175 mg/m2), cetuximab (initial dose of 400 mg/m2 with subsequent weekly doses of 250 mg/m2 intravenously), and four sessions of hyperthermia for cervical lymph node metastases. The patient responded well to the therapy, with a complete response of the primary tumor. Radical neck dissection was performed with reconstructive surgery, including resection of the overlying skin. A pathologic complete response was achieved for the N3 and all other cervical lymph node metastases. The patient showed no evidence of recurrence in the 3 years following treatment. Based on the findings in the present case, the use of retrograde superselective intra-arterial chemoradiotherapy combined with hyperthermia and cetuximab seems to be a promising modality for patients with N3 cervical lymph node metastasis of oral cancer.