A pneumatic tire having an improved noise performance without deteriorating the drainage performance and having in a tread portion at least one circumferential main groove 3 which extend continuously in the tire circumferential direction, wherein the circumferential main groove 3 has a pair of groove walls 6, and in at least one of the groove walls 6 are provided at intervals in the tire circumferential direction a plurality of fine grooves 9 each of which extends in the tire radial direction and is provided in at least a part of its inner surface with a non-flat portion 10 extending in a wave-like form in its length direction.