PROBLEM TO BE SOLVED: To achieve large force by increasing a distance of a movement of an actuation member, even when a pneumatic actuator which moves the actuation member by using the pressure of gas, such as air, is made smaller in the size.SOLUTION: A pressure actuator includes a dual cylindrical body 11 one end of which is folded into the inside thereof and which has an internal space extending from a side of the other end to a folded portion, an elongated actuation member 12 connecting to and extending outward from a closing part which connects the one end and the other end of the dual cylindrical body 11, and a gas guiding tube (air supply and discharge means) 13 communicating with the internal space of the dual cylindrical body 11.SELECTED DRAWING: Figure 2【課題】 空気等の気体の圧力を利用して作動用部材を移動させる空気圧式アクチュエーターを小型化させた場合にも、作動用部材を距離させる移動を大きくして、大きな力を得られるようにする。【解決手段】 その一端を内部に折り返して、他端側から折り返しの部分に向かって拡がる内部空間を有する2重筒状体11と、前記の2重筒状体11の一端と他端とを連結してなる閉塞部に連結して外部へ延出した長尺状の作動用部材12と、前記の2重筒状体11の内部空間に連通した気体案内管(給排気手段)13と、を備えるようにした。【選択図】 図2
