We here describe a case of advanced breast cancer (Stage IV) in which an oral S-1+TAM therapy following a primary systemic chemo-radiotherapy has been effective in maintaining the patient's QOL. A 40-year-old woman visited our hospital because of her left breast tumor. On physical examination, the tumor had invaded to the skin adjacent to the nipple forming a skin ulcer and marked deformity of the entire breast. Also noted were swollen lymph nodes in the left armpit. Subsequently, radiographic imaging tests revealed that the tumor had metastasized to the liver and lungs, as well as the skull. Accordingly, a primary systemic chemotherapy (4 series of AC/T) was started and followed by local radiation therapy (60 Gys) immediately after completing the chemotherapy. The metastasizing lesions in the liver, lungs, and skull had markedly reduced in the size and number, and the skin ulceration had healed up by these treatments. Afterwards, she has been given TAM daily and S-1 for 4 weeks with a 2-week interval. She has been quite well without any adverse effects by S-1 and TAM, and the primary as well as metastasizing lesions remain stable with normalized tumor marker levels (NC) for nearly 3 years.