The authors investigated, using model specimens made of Acryle Resin, the shear rigidity of transverse bulkheads in wing tank for large tankers. By test of tight bulkhead models, the effect of aspect ratio on the shear rigidity is quantitatively clarified. Further the effect of deck and bottom plates is investigated. By test of swash bulkhead models with various types of opening, the effect of opening area ratio and the shapes of opening are made clear. Fundamental data show the effect of deck and bottom plates, is also obtained.