It is found that the amount of wear of a tread rubber of a tire, which is abandoned as wear life of the tread rubber expires, is not uniform over the entire width, and there is a high correlation between distribution in the tread width direction of the remaining thickness of the tread rubber of the abandoned tire and distribution in the tread width direction of wear effective rubber volume. On the basis of this finding, it is possible to improve wear life of a pneumatic tire 1, by making volume distribution of a base rubber layer 8 of a tread rubber 4, which has a layered structure, equal to distribution of the wear effective rubber layer, so that the tread rubber 4 wears equally in the tread width direction.