A pneumatic tire comprises a carcass ply of cords extending between bead portions through a tread portion and sidewall portions, the carcass cords include main cords (10M) for reinforcing purpose and auxiliary cords (105) for controlling the outflow of topping rubber during vulcanization, the main cords and auxiliary cords are arranged alternately in the tire circumferential direction, and the number of auxiliary cord(s) between the main cords is in a range of from one to three.