A method is provided for producing a weight-reduced FRP cylinder which can attain high strength, and also such an FRP cylinder is provided. This FRP cylinder producing method, in which a plurality of prepregs formed by impregnating reinforced fibers with thermosetting resin sheets are wound into a cylinder and thermally cured to be formed as a plurality of FRP layers, includes a simultaneous multilayer winding process in which a torsional rigidity retaining prepreg and a buckling prevention prepreg are continuously wound a plurality of turns with being layered on each other when the plurality of prepregs are wound into a cylinder, wherein the torsional rigidity retaining prepreg includes a layer of fibers oblique to a cylindrical axis direction of the FRP cylinder, and wherein the buckling prevention prepreg includes a layer of fibers orthogonal to the cylindrical axis direction.