In this research focuses on the development of a supporter for osteoarthritis of the knee. At first, as approach of this study, the movement of the knee joint of a healthy person is measured. From provided measurement data, the movement of the general knee joint is modelled. A model with 3 degree-of-freedom is used to reproduce the rotation generated in synchronism with the operation to stretch or bend the knee. Based on a provided model, the supporter reproducing the movement of the general knee joint is designed. In order to reproduce the complex movement of rotation movement to synchronization with the flexion and extension of the knee, the mechanism using the curve-shaped cylinders are suggested. It was confirmed that the movement of the general knee joint could reappear by a designed supporter by simulation using the 3D CAD.