In this paper, a postural supporting device using a balloon actuator-sensor system (BASS) is proposed for the person with disability who is unable to move their body because of injury or disease. The BASS is able to control the position and stiffness adaptively using an adaptive learning impedance controller. The pneumatic actuator has excellent compliance and flexibility, therefore that is good for the human-mechanical system. However, it also has nonlinearity, hence high precision control is difficult. Therefore, in this paper, the CMAC-PID control scheme is installed. The control performance of the BASS is evaluated by the control experiment.