PURPOSE: To provide the lightweight pneumatic radial tire excellent in riding touch and steering stability.

CONSTITUTION: The pneumatic radial tire containing carcasses comprising the plies of radially arranged cords extended in a toroid-like state between a pair of beads as carcasses is characterized by employing cords each comprising at least two sheaths 2 consisting of steel filaments and a core consisting of an organic filament as the carcasses, the steel filaments being arranged along the peripheral surface of the cord in proximity to each other in a structure of 1+N (N is 2-4).