The treatment of early breast cancer using oncoplastic breast surgery (OBS) has been gradually increasing in popularity and is recognized for its efficacy in local control and excellent cosmetic results. We herein report a useful technique for obtaining symmetry of the breast shape for an early breast lesion located in an outer area, close to the nipple-areola, in a Japanese patient with ptotic, fatty breasts. We designed two equilateral triangles: one just upon the resected area and the other on the axilla. They were located on a straight line, with one top pointed to the cranial side and one to the caudal side. A crescent area around the areola was de-epithelialized in the 12 o’clock and 6 o’clock directions. Columnar-shaped breast tissue and an equilateral triangular skin flap and fatty tissue were removed together. To fill the defect, a skin-glandular flap was slid horizontally after suturing the inframammary line. Although an incision scar was formed on the breast and lateral chest wall in a Z-shape, this new technique was able to achieve not only cancer control but also excellent cosmetic results.