PURPOSE: To suppress the separation of the fiber covered rubber of the carcass by arranging a buffer rubber layer whose modulus is larger than that of the covered rubber and smaller than that of the rubber filler between the carcass body and the rubber filler at the height of a ply fold-back part end to disperse the shearing distortion.

CONSTITUTION: In a tire 1, a carcass 2 made of the rubber covered ply of the fiber oriented in the radial direction consists of the carcass body 21 folded back around a pair of bead cores 3 and the rubber filler 4 and a ply fold-back part 22, and a ply fold-back part end 23 is located on the inner side of the position 5 of the sectional width of the tire. A first buffer rubber layer 6 whose modulus is larger than that of the fiber covered rubber of the carcass and smaller than that of the rubber filler is provided between the carcass body 21 and the rubber filler 4 at the height of the ply fold-back part end 23, and a second buffer rubber layer 7 whose modulus is larger than that of the fiber covered rubber and smaller than that of the rubber filler is provided between the carcass body at the upper end part of the rubber filler and the rubber filler.