PURPOSE: To prevent the occurrence of ply separation trouble, by a method wherein, in a pneumatic tyre having a carcass body in a bias construction formed with a plurality of ply laminations, a distance between the cords of the carcass plies is kept properly.

CONSTITUTION: In a subject tyre, a bead part 1 consists of, for example, three bead cores 1aW1c, and a ply 2, with which a carcass body is formed, consists of a plurality of ply laminations 2a and 2c in which a large number of organic fiber cords, for example, nylon cords, are arranged for being coated with rubber. Space indexes Γi and Γo between cords of plies which adjoin between a middle layer group 2b and an inner layer group 2a and between cords of plies which adjoin between the middle layer group 2b and an outer layer group 2c, and space inexes Λi and Λo between cords in the same ply are set within a range of 1.1<Γi, Γo<3.0, 1.5<Λi, and Λo<4.0. Based on the total number of plies, a number of plies of the middle layer group 2b, the inner layer group 2a, and the outer layer group 2c are determined so as to be 0.8nW0.6n, 0.1nW0.2n, and 0.1nW0.2n, respectively.