A pneumatic tire comprises a pair of bead portions, a pair of sidewall portion, a tread portion, a radial carcass of at least one ply, and a belt, wherein the tread portion is provided with two or more circumferential main grooves formed in a tread rubber at an inner region sandwiched by both shoulder regions and one or more circumferential ribs defined by two adjoining circumferential main grooves, and at least two circumferential fine grooves are formed in the circumferential rib.