[Problem] To avoid loosening of a boss screw from a liner in a step of winding reinforcing fibers of a pressure vessel. [Solution] A liner 12 and a tail boss 32 are provided with rotation-suppressing parts in the form of a protrusion 42 and a recess 44, which inhibit the tail boss 32 from rotating relative to the liner 12 in a direction in which a male screw 28 and a female screw 34 loosen.
