Radiation therapy (RT) is one of the definitive treatments for early-stage nasal vestibular carcinoma and has similar local control rates to resection surgery. There are various methods, including external beam RT and brachytherapy. This report describes a case who showed local control for more than 5 years after brachytherapy alone using Au-198 grains for nasal vestibular carcinoma. A 68-year-old Japanese man complained of swelling and pain in his left nasal cavity. He was diagnosed with squamous cell carcinoma (SCC) (cT1N0M0, stage I). An elevated mass of 8 mm in long diameter was found inside the left nasal cavity. Since the patient selected brachytherapy, nine Au-198 grains 185 mBq were permanently injected percutaneously under local anesthesia, and 85 Gy was prescribed. Grade three dermatitis was observed as an acute adverse event. After 2 years, mild telangiectasia of the left nasal skin and epilation of nasal hair in the left nasal cavity was regarded as late adverse events. The patient continues to keep a complete response for 5 years. For small nasal vestibular SCC, brachytherapy with Au-198 grains might be a good option.