BackgroundAlthough various endoscopic surgery robots developed in previous studies are versatile and have high lesion accessibility, they have limitations in terms of reaching the target lesion through the curved path in the large intestine and providing a stable tasking environment for the operator. MethodsAn endoscopic surgery robot was developed for performing surgery in the large intestine. The robot was easily inserted into the target lesion in the curved colon through the mounted soft actuator and demonstrated high structural stiffness through the insertion of the sigmoidal auxiliary tendons. ResultsThe robot was able to access the target lesion in the curved colon through teleoperation alone. Further, it was confirmed that the high structural stiffness overtube improved the overall task performance in the user test. ConclusionsThe proposed robotic system demonstrated the possibility and potential of performing advanced endoscopic surgery in the large intestine.