In our previous papers, the torsional strength and rigidity of container ship are reported, but in this paper described is the transverse strength of hull being one of the serious problems of container ship with long and wide hatch opening. To examine the transverse strength, the double bottom and side structure were substituted to plane structure and analyzed by using computer. Summary results were obtained as follows. 1) The ballast condition is the severest among of several loading conditions. 2) Where the double hull changes to the single hull in the middle of the hold, the stress is the higher in the vicinity of this area. 3) When a deep floor equal to the height of a container was fitted, the shear force of the floor and the bending moment of the center girder decreased by about 20 and 10 percent, respectively. 4) The value of the mutual friction between containers and between a container and the ship's bottom has no direct effect on the stress of the floor and the girders that were being considered here. 5) The shear force on the double hull part and the axial stress on the transverse box girder were not so large to cause problem.