A pneumatic tire including: a tread portion and a belt layer on an outer periphery of a carcass layer that extends between left and right bead portions and a plurality of circumferential main grooves extending in a tire circumferential direction provided on an outer surface of the tread portion, wherein on a tire cavity side surface of the tread portion, a ridge (Ra) protruding into the tire cavity side in a direction opposite to a tire radial direction is formed that extends in the tire circumferential direction in a position offset from a tire center towards a well side of a mounting rim so as to encompass an entire width of a well and an entire width of a circumferential main groove positioned farthest to a shoulder side.