A tire comprising a carcass of a framework toroidally extending across a pair of bead cores, and comprising a belt and a tread in order on an outer side of the carcass in a tire radial direction, wherein a tread half portion (5x, 5y) on one side of the tread via a tire equatorial plane as a boundary has at least a circumferential groove and a plurality of land portions located on both sides of the groove, an outline of a tread surface (6a, 6b) of the tread half portion (5x, 5y) in tire widthwise cross-sectional view includes a plurality of circular arcs having different radii of curvatures, and the circular arc having a minimum radius of curvature among the plurality of circular arcs is present within the outline of the land portion adjacent to a tread edge, and the tread half portion (5x, 5y) has a base rubber layer, and a cap rubber layer laminated on an outer side of the base rubber layer in the tire radial direction, characterized in that the base rubber layer has a lower storage modulus than the cap rubber layer, and an end of the base rubber layer in a tire width direction on a tread edge side is located in a region extending as much as 0.06 times a ground contact width of the tread half portion (5x, 5y) on each of both tire widthwise sides of a center of a tire widthwise length of an outline portion occupied by the circular arc having the minimum radius of curvature, wherein the storage modulus is measured at room temperature of 25°C, a frequency of 52 Hz, an initial strain rate of 2%, and a dynamic strain rate of 2% by use of a viscoelasticity meter, wherein the tread edge means a tire widthwise ground contact edge of the tire in a case where the tire mounted to an applicable rim is disposed vertically to a flat plate at a prescribed air pressure in a stationary state, and is loaded with a load corresponding to a prescribed mass, and the outline is an outline of the tread surface in a tire widthwise cross section of the tire mounted to the applicable rim in a state where the tire is filled with a prescribed internal pressure and loaded with a prescribed load. wherein a tread half portion (5x, 5y) on one side of the tread via a tire equatorial plane as a boundary has at least a circumferential groove and a plurality of land portions located on both sides of the groove, an outline of a tread surface (6a, 6b) of the tread half portion (5x, 5y) in tire widthwise cross-sectional view includes a plurality of circular arcs having different radii of curvatures, and the circular arc having a minimum radius of curvature among the plurality of circular arcs is present within the outline of the land portion adjacent to a tread edge, and the tread half portion (5x, 5y) has a base rubber layer, and a cap rubber layer laminated on an outer side of the base rubber layer in the tire radial direction, characterized in that the base rubber layer has a lower storage modulus than the cap rubber layer, and an end of the base rubber layer in a tire width direction on a tread edge side is located in a region extending as much as 0.06 times a ground contact width of the tread half portion (5x, 5y) on each of both tire widthwise sides of a center of a tire widthwise length of an outline portion occupied by the circular arc having the minimum radius of curvature, wherein the storage modulus is measured at room temperature of 25°C, a frequency of 52 Hz, an initial strain rate of 2%, and a dynamic strain rate of 2% by use of a viscoelasticity meter, wherein the tread edge means a tire widthwise ground contact edge of the tire in a case where the tire mounted to an applicable rim is disposed vertically to a flat plate at a prescribed air pressure in a stationary state, and is loaded with a load corresponding to a prescribed mass, and the outline is an outline of the tread surface in a tire widthwise cross section of the tire mounted to the applicable rim in a state where the tire is filled with a prescribed internal pressure and loaded with a prescribed load.