Inflatable tubes are expected to be one of the primary structural elements for constructing the large deployable space structures for the light weight property.Also, the flexible feature of inflatable tube is applicable for joint elements and hinge elements for space suits.However, few research works to design the inflatable tubes is performed because the structural properties of the inflatable tubes are complicated due to the thin wall flexible membrane materials of the tubes.Thus, many research works for inflatable structures are focused on the applications and the structural properties using precise finite model as same as some theoretical approaches to investigate the structural properties of the inflatable tubes are performed by Comer1, and Main2.These researches are based on the assumption of uniform circular cross-section configuration after collapsing the inflatable tubes.Moreover, the cross-sectional deformations are sensitive to evaluate the structural properties of the inflatable tubes in detail.Sakamoto3 and Furuya4 introduced the effects of cross-sectional deformation into the numerical analyses and the experiments, respectively.