The purpose of this research is to propose a design of a clinically relevant upper-limb (hand, wrist, and elbow) exoskeleton that meets the clinical requirements. At first, the proposed robot was designed to have sufficient torque for passive exercise therapy and spasticity measurement of post-stroke patients with spasticity (grade 3 or lower in Modified Ashworth Scale). Because the therapy of patients with high level spasticity could be laborious for therapists by increased muscle tone, and the patients tend not to get enough rehabilitation treatment. Secondly, this robot was designed to have user friendly features like as modularity, so that users have easy approach to assemble and disassemble for practical use. Thirdly, this robot system was designed to guarantee the safety for robot-aided passive training of patients with spasticity. As a result, we were able to see the usability of the robot system, even though it was a pilot test. This shows the possibility of measuring and classifying the spasticity.