A new pneumatic linear actuator made of a thin flexible rubber is developed for locomotion in narrow paces. The actuator is named "tetra chamber actuator". This new actuator has an ability of object transportation and locomotion. The actuator was designed based on non-linear FEM analysis considering geometrical and material nonlinearity, fabricated and evaluated. The working principle of this actuator is based on a traveling elastic deformation wave drive and the actuator was designed to generate large track of the deformation and to have an ability of bidirectional propelling. The actuator shape was designed in detail using nonlinear FEM analysis and was fabricated by CAD/CAM system based on the results of analysis. The prototype is 10×10mm in size. The experiments were made about its basic characteristics and object transportation ability. The prototype generates the motion about six times larger than that of conventional similar actuators to show its great potential.