This paper describes a structural analysis of rehabilitation robots intended for upper-limb post-stroke therapy. First, the functions of the robots required for restoration of motor function are explained and the according conditions that should be satisfied by the robots are introduced. Second, the analytical methods to judge if the conditions are satisfied for a given robot structure are proposed, and they are explained by using a planer robot. Then, the methods are applied to the structure of the proposed escort type rehabilitation robot for spatial motions and their validity is investigated.