An artificial rubber muscle as an actuator was paid attention in this study because the manipulator was found to be safe to human when it comes in contact with human. However, this actuator vibrates easily with a late response because of the applied air pressure. Then, the magnetorheological brake that uses the magnetorheological fluid with an early response is built into the joint and controls the vibration. In this article, we have grasped the dynamic characteristics of a manipulator by the construction of a model for improvement in the control performance of the magnetorheological brake. Furthermore, the simulation was performed using the model, and efficient braking of the magnetorheological brake was examined.