A 61-year-old man was pointed out a small peripheral lung nodule and mediastinal lymph node swelling on the chest computed tomography (CT). At the operation, it was diagnosed squamous cell carcinoma and right upper lobectomy and nodal dissection were done. The tumor was 9 mm in size and diagnosed as well differentiated squamous cell carcinoma with metastasis to mediastinal lymph nodes. Postoperative radiotherapy was done (50 Gy). The patient is doing well without apparent recurrence 33 months after surgery. We reported a case of peripheral small squamous cell carcinoma (9 mm) of the lung with metastasis to mediastinal lymph nodes.