Abstract—To reduce the inspection cost of water supply pipe, various pipe inspection robots have been developed. In the previous study, a novel pipe inspection robot using a flexible pneumatic cylinder and pipe holding mechanism that could move forward along to the pipe by changing the robot’s body naturally was proposed and tested. In this paper, to improve its mobility and responsibility, a pipe holding mechanism using an extension type flexible pneumatic actuator whose volume change is smaller than the previous one using a balloon is proposed and tested. In addition, to change the travelling direction of the robot, a compact bending unit using shorter extension type flexible actuators is proposed and tested. As a result of its driving test, the tested thin holding mechanism can hold a pipe without increasing its longitudinal length.The tested bending unit can bend 90 deg. toward every radial direction with the length of the unit becomes two-third short from the previous one.