A pressure vessel arranging and integrating a plurality of vessel structures each including a cylindrical liner opened at both ends and a fiber reinforced resin layer covering the outer periphery of the peripheral wall of the liner. Dome-shaped communicating members bulging outward are fixed across both respective ends of the liners of the vessel structures, thereby making the interiors of these liners communicate with each other and closing the open ends of these liners. This pressure vessel can be installed with no wasted space, and also allows an increase in capacity.