To provide a reinforcing cord material properly usable as a reinforcing material of a rubber product or the like in various fields, particularly as a cap ply layer (belt reinforcing layer) of a tire, having excellent mechanical characteristics such as rigidity and thermal characteristics, and reducing only loss.

Polyamide fiber cords are buried in rubber to form this reinforcing cord material, and the dynamic loss tangent tan δ of the polyamide fiber cords in the rubber at 120°C is below 0.065. A case that the dynamic loss tangent tan δ is below 0.055, a case that the polyamide fiber cord is a 66 nylon cord, a case that the twist coefficient Kt of the polyamide fiber cord is 0.2-0.7, a case that the surface of the polyamide fiber cord is coated with an RFL(resorcinol-formalin resin-latex) adhesive, and a case that the reinforcing cord material is used for the cap ply layer of the tire are preferable.