To strengthen limbs which are injured in an accident, a traditional rehabilitation device has been adopted. However, it is heavy and complex, a light-weight body joint bending actuator which is made of a Shape Memory Alloy (SMA) and is simpler than traditional rehabilitation devices is therefore proposed. Here, an SMA-made actuator can offer the resistance needed for a rehabilitation program. A Ti-Ni based SMA is adopted for the body joint bending actuator. To facilitate the swinging angle and the related bending torque, various structures of the SMA-made body joint bending actuators (a one-bunch SMA actuator and a six-bunch SMA actuator) have been adjusted in the experimental work by varying the number of SMA fibers in a bounded bunch. Results reveal that the structure-A (a six-bunch SMA fiber with 8 fibers per bunch) and the structure-B (a one-bunch SMA actuator with 50 fibers per bunch) have similar functions- the bending angle is 158° and the maximum bending torque is 0.155 Nm. Moreover, depending on the patients condition, both the maximum swinging angle and the velocity are adjustable by the patient via the PC-based control system. In addition, to avoid damage to the actuator, a maximum operating temperature of 90°C is preset on the SMA.