Because the colon is soft and complex shape, current colonoscopy is not easy and depends on doctor's skill strongly. The purpose of this research is realization of a novel large intestine endoscope which can change own stiffness partially. By changing the stiffness, overload to the inner wall of the large intestine can be avoided. The developed endoscope consists of multiple stiffness change devices. The device is configured with fiber-reinforced silicone rubber and its stiffness can be controlled by air pressure. Previously we fabricated a prototype stiffness change device, however the changing range of it was not enough. In this paper, to improve characteristics of the device, we increase the number of reinforced fibers and introduce new driving system which controls not only positive pressure but also negative pressure. In addition, two new prototypes of the endoscope are developed. The effectiveness has been verified by insertion experiments in U-shaped route and the large intestine model.