A pneumatic radial tire includes a belt layer consisting of a plurality of belt plies reinforced by cords. The cords of at least two adjacent belt plies are oblique in opposite directions with respect to an equatorial plane of the tire. The tire comprises a relieving ply overlapping the belt plies. A modulus of the relieving ply is less than that of the belt plies. A width of the relieving ply is wider than that of the belt ply having the widest width. Cords reinforcing the relieving ply is oblique with respect to the equatorial plane in the same directions as those of cords of the belt ply having the widest width. Separations at belt ends of the maximum width belt ply is effectively prevented.