Recently, virtual reality systems that feed back to human senses have only been realized as visual and acoustic feedback. However, they are not enough to realize the force feedback system for hands, arms, legs and so on. The actuators required for such a system need to be flexible so as not to injure the body. The purpose of our study is to develop a flexible and lightweight actuator which can be safe enough to be attached to the human body. We propose new types of flexible pneumatic actuator that can be used even if the actuator is deformed by external force. In this study, we tested rodless type flexible pneumatic cylinders that have a self holding function for positioning under the condition of no supply pressure. We also developed a new type of McKibben artificial muscle that has a long stroke of more than 80% of its original length. As a result of our experiment, we can confirm that the tested cylinder is useful to be applied in a positioning system because it consumes less air under the condition of holding. By using the tested Mckibben actuator, we can realize a long stroke lifting motion of a dumbbell whose mass is 6kg.