The ideally inflatable structure is a fold-up structure that can be completely stably extended its shape by internal pressure. In order to transport a huge structure in the space, there are many problems especially the cost of transportation. From this reason, small and light structure is required. By using inflatable structure, it is possible to make a really small and light structure for transportation that can be extended to be a huge structure later so it is expected that the inflatable structure will be used for the structures in the space application. However using inflatable structure has some difficulties, especially controlling posture to be stable in the process of extension. In the extension phase, it is quite hard to control internal pressure in order to maintain the stability of inflatable structure. Our laboratory researches on 1 degree of freedom inflatable tube that can be extended and folded. We were seeking for the method to fold the tube that can be stably extended by comparing with many kinds of fold methods. In order to verify that our tube can be stably extended in the space or not, we have to do an experiment in the situation that there is no effect of gravity, so we did an experiment by parabolic flight that can generate micro gravity condition. From this experiment, our tube could be stably extended but it still needs to be improved. Now we are in the process of building vision and simulation system to analysis and evaluate the result in order to figure out the way to design a perfect inflatable tube.