An aircraft water tank includes a conical surface of a skirt portion and a conical surface of an inner liner attached together using an adhesive, with an identical adhesive used in forming a fiber-reinforced resin layer on the inner liner via a filament winding method. When attaching with the adhesive, the adhesive is expelled at the outer circumferential edge of the skirt portion from between the conical surface of the skirt portion and the conical surface of the inner liner. Reinforcement fibers are applied on top of the protruding adhesive, and the adhesive impregnates into the reinforcement fibers. The protruding adhesive and the reinforcement fibers form a reinforcing member which connects a uniform stress surface of the skirt portion to a uniform stress surface of the inner liner located radially outward of the skirt portion.