A 60-year-old woman was diagnosed with simultaneous double cancer of the inguinal lymph node(squamous cell carcinoma) and the right lung(combined small cell carcinoma; cT3N0M0, Stage ⅡB)after observing and reporting a right inguinal swelling. Both were local lesions, and standard definitive treatments were administered. Right inguinal malignant tumor resection and right femoral arteriovenous resection with artificial blood vessel replacement and pedicled transverse rectus abdominis musculocutaneous flap were performed for the unknown primary cancer. Right upper lobectomy, lymph node dissection, and chest wall resection were performed for the right lung cancer. The postoperative stage of the right lung cancer was pT3N0M0, Stage ⅡB, and cisplatin(CDDP)/vinorelbine(VNR)was administered as postoperative adjuvant chemotherapy. The 2 surgeries and adjuvant chemotherapy were well-tolerated, and there has been no recurrence for 1 year and 5 months.