HEAVY-DUTY PNEUMATIC TIRE

The present invention aims at providing a heavy-duty pneumatic tire capable of suppressing interlayer separation in the belt by enhancing the rigidity of the belt without increasing the tire mass. Accordingly, tire 2 has a tread 4, a pair of sidewalls 6, a pair of beads 10, a carcass 12 and a belt 18. The belt 18 is provided with multiple plies (18a, 18b, 18c, 18d) laminated in a tire radial direction; each ply has numerous cords arranged in parallel and a topping rubber; the cord has a 1×4 single-strand structure; the ratio (A) (=F/E) of flexural rigidity (F) to tensile strength (E) per cord is 0.090¤A¤0.112, and tensile strength (E) per cord is 1550N¤E¤1750N.