Minimally invasive surgery has become a standard options of surgery. We have introduced a master-slave manipulator "da Vinci" to the clinical situation in July 2000, and developed new operative techniques, which are safer and more tender for patients than before. Up to now, a total of 45 patients underwent a robot-assisted endoscopic surgery using "da Vinci" system. Several procedures including laparoscopic splenectomy and thoracoscopic mediastinal tumor extirpation were first performed in the world. This system provided surgeons with motion scaling, physiological tremor elimination, and high-resolution 3-dimensional vision. Thanks to those sophisticated functions, all surgical procedures, which have been limited due to endoscopic circumstances, were performed much easily and safely than before. Every effort to develop a new type of robotic has been made in collaboration with other fields of scientists. A next-generation robotic surgery is required to equip new functions including tactile sensation system, a real-time navigation system and tele-operation system. Robotic surgery is believed to be one of the most promising and important fields of surgery in the near future.