A robot chair is developed to support mobility of elderly and disabled people living in the house where steep and narrow stairways are installed. In order to deal with such mobility problem the developed robot chair has a compact original configuration. The robot chair is vertically moved by actuation of electric cylinders and horizontally moved by push-pull operation given by an attendant. In order to navigate safely every action of the chair is checked by the operator. Up and down motions of the robot chair on the stairway are executed through combinations of motor and cylinder actuations. Performance of the robot chair was evaluated through two kinds of experiments. The excellent ability of the robot chair could be confirmed through these experiments.