A pneumatic tire comprising: a tread portion provided with four circumferentially continuously extending main grooves including a pair of crown main grooves and a pair of shoulder main grooves so that the tread portion is axially divided into five land regions including a crown land region disposed on the tire equator, two axially outermost shoulder land regions and two middle land regions, wherein the shoulder land regions are each provided with shoulder lug grooves each extending axially inwardly from the tread edge (Tel, Te2) to an axially inner end within the shoulder land region, in a meridional cross section of the tire under a normally inflated unloaded condition, the tread portion is provided with a tread profile made up of a crown tread profile including the tire equator, a middle tread profile on each side of the crown tread profile, and a shoulder tread profile on the axially outside of each of the middle tread profiles, wherein the crown tread profile which is a radially outwardly convexed arc having a radius of curvature Rc that is 500 to 2500 mm, the middle tread profile which is a radially outwardly convexed arc having a radius of curvature Rm, and the shoulder tread profile which is a radially outwardly convexed arc having a radius of curvature Rs satisfy a magnitude relation Rc > Rm > Rs, wherein the radius of curvature Rs is 0.15 to 0.35 times the radius of curvature Rc, first interconnecting positions at which the crown tread profile connects with the middle tread profiles are positioned in the respective middle land regions, and second interconnecting positions at which the middle tread profiles connect with the shoulder tread profiles are positioned in the respective shoulder land regions and axially inside the inner ends of the shoulder lug grooves, characterized in that the crown land region and the middle land regions are provided with only sipes defined as having a width of less than 2 mm, and the shoulder land regions are each provided with connecting sipes extending from the axially inner ends of the respective shoulder lug grooves to the shoulder main groove, wherein the radius of curvature Rm is 0.50 to 0.70 times the radius of curvature Rc. a tread portion provided with four circumferentially continuously extending main grooves including a pair of crown main grooves and a pair of shoulder main grooves so that the tread portion is axially divided into five land regions including a crown land region disposed on the tire equator, two axially outermost shoulder land regions and two middle land regions, wherein the shoulder land regions are each provided with shoulder lug grooves each extending axially inwardly from the tread edge (Tel, Te2) to an axially inner end within the shoulder land region, in a meridional cross section of the tire under a normally inflated unloaded condition, the tread portion is provided with a tread profile made up of a crown tread profile including the tire equator, a middle tread profile on each side of the crown tread profile, and a shoulder tread profile on the axially outside of each of the middle tread profiles, wherein the crown tread profile which is a radially outwardly convexed arc having a radius of curvature Rc that is 500 to 2500 mm, the middle tread profile which is a radially outwardly convexed arc having a radius of curvature Rm, and the shoulder tread profile which is a radially outwardly convexed arc having a radius of curvature Rs satisfy a magnitude relation Rc > Rm > Rs, wherein the radius of curvature Rs is 0.15 to 0.35 times the radius of curvature Rc, first interconnecting positions at which the crown tread profile connects with the middle tread profiles are positioned in the respective middle land regions, and second interconnecting positions at which the middle tread profiles connect with the shoulder tread profiles are positioned in the respective shoulder land regions and axially inside the inner ends of the shoulder lug grooves, characterized in that the crown land region and the middle land regions are provided with only sipes defined as having a width of less than 2 mm, and the shoulder land regions are each provided with connecting sipes extending from the axially inner ends of the respective shoulder lug grooves to the shoulder main groove, wherein the radius of curvature Rm is 0.50 to 0.70 times the radius of curvature Rc.