The application of robot to rehabilitation has become a matter of great concern. This study deals with an exercise for restoration of function being one of important rehabilitation tasks. An exercise of single joint has already been achieved with some automatically controlled machines. Now, the multi-joint exercise becomes desirable. which requires the exercise robot with multi-degrees of freedom to generate more realistic motion. pattern. This I;ind of robot has to be absolutely safe for human. A pneumatic actuator may be so effective for such a robot because of the flexibility from air compressibility that a rubber artificial muscle manipulator pneumatically driven is applied to construct the exercise robot with two degrees of freedom. Also an impedance control strategy is employed to realize various exercise motion modes. Further. an identification method of the recovery condition is proposed to execute the effective rehabilitation. Some experiments show the availability of proposed rehabilitation robot system.