To provide a method of manufacturing a pneumatic radial tire, reducing rolling resistance while securing steering stability and durability.

Inside belt ply 5 including an organic fiber cord arranged so as to be inclined to a tire circumferential direction is molded into a cylindrical shape, and a diameter of the inside belt ply 5 molded into the cylindrical shape is expanded. A pair of split ply pieces 4a and 4b constituting a carcass ply 4 is disposed. The center area of the inside belt ply 5 is opened, while covering both end areas of the inside belt ply 5 with the ends of the pair of split ply pieces 4a and 4b. An outside belt ply 6 including a steel cord arranged so as to be inclined to the tire circumferential direction and opposite to the organic fiber cord is molded into the cylindrical shape. The ends of the split ply pieces 4a and 4b are held by the inside belt ply 5 and the outside belt ply 6.