In recent years, robotic technology has been introduced to medical fields and many surgical robots have been presented not only in academic fields but also as commercialized products. In this paper, an outer shell type 2 DOF bending manipulator using a spring-link mechanism is presented. The mechanism was developed for a surgical robot, which can implement various surgical treatment devices inside of the manipulator. The spring-link mechanism is a simple combination of a flat spring and a rigid link with a passive joint connection. The outer shell type 2 DOF bending manipulator is composed by four spring-link mechanisms. The most unique feature of the manipulator is that these four springs are interconnected in the kinematics. Therefore, it is possible to realize a robust and backlash-free motion by taking into account the interconnections of springs such as an internal stress of the structure. In addition, by locating four spring-link mechanisms around the manipulator, it is possible to place medical devices inside of the manipulator.