To attain the reduction of weight while maintaining traveling durability equivalent to a current one by reducing a rigidity difference in level between cord rubber, in a pneumatic radial tire for heavy load.

This tire 1 is provided with a pair of bead cores 2, a carcass ply 3, reinforcing layers 4 and 5, and a belt layer 6. The carcass ply 3 is made of organic fiber cords and coating rubber. The organic fiber cords are made of polyketone fibers substantially made of repeating units shown in a formula (I). The coating rubber has 100% elongation time modulus of 2.5 to 4.5 MPa. In the formula (I), A is a part derived from an ethylenically unsaturated compound polymerized by ethylenic bonding and may be the same or different in each of the repeating units.