A pneumatic tire includes on a tread a plurality of circumferential main grooves extending in the tire circumferential direction, and a plurality of land portions formed by being partitioned by the circumferential main grooves. A protrusion is formed on a groove bottom of at least one of the circumferential main grooves. The protrusion continuously extends in a groove-length direction of the circumferential main groove, and a height h1 of the protrusion varies in a wavelike form along the groove-length direction. Moreover, junctions each of which couples the protrusion onto at least one of groove walls of the circumferential main groove are formed on the groove bottom of the circumferential main groove.