Endoscopic surgery is characterized by the creation of a working space. At our department, we have obtained good results with a retromammary space approach in which the tumor is resected after creation of a working space in the retromammary space. The special instruments used for this purpose comprise an endoscopic vein harvesting system to dissect the retromammary space, a dissecting balloon to compress the space to achieve hemostasis, and laparosonic coagulating shears to incise the tumor. This surgical technique provides a superior cosmetic result, and the level of patient satisfaction has been high.