A tread surface of a pneumatic tire is configured so that, given an inner region inward from shoulder circumferential main grooves in a tire lateral direction, and outer regions outward from the shoulder circumferential main grooves in the tire lateral direction, blocks positioned in the inner region are defined into three or more small blocks by narrow grooves, and blocks positioned in the outer regions are defined into a number of small blocks by the narrow grooves, the number being at least one less than the number of small blocks defined in the blocks positioned in the inner region. The small blocks including frontmost portions of the blocks in a tire rotation direction are leading-side blocks, and the small blocks including backmost portions of the blocks in the tire rotation direction are trailing-side blocks. The leading-side blocks have a surface area that is less than that of the trailing-side blocks.