A non-pneumatic tire comprising: - an inner annular portion; - an outer annular portion provided concentrically on an outer side of the inner annular portion; - a plurality of coupling portions (3, 31, 32) coupling the inner annular portion and the outer annular portion to each other; - a tread provided on an outer side of the outer annular portion; wherein the plurality of coupling portions comprises a plurality of first coupling portions and a plurality of second coupling portions, which are alternately arrayed with each other along the tire circumferential direction, wherein each of the first coupling portions is extended from one side in the tire width direction of the inner annular portion toward other side in the tire width direction of the outer annular portion and each of the second coupling portions is extended from the other side in the tire width direction of the inner annular portion toward the one side in the tire width direction of the outer annular portion 2, in a way that the first coupling portion and the second coupling portion, which are adjacent to each other, are disposed in a substantially X shape when viewed from the tire circumferential direction, wherein each of the plurality of first coupling portions includes an inner connecting portion (3 1a) connected to the inner annular portion and an outer connecting portion connected to the outer annular portion and each of the plurality of second coupling portions includes an inner connecting portion connected to the inner annular portion and an outer connecting portion connected to the outer annular portion, wherein the tread includes a first annular connecting portion region, which overlaps the outer connecting portions of the first coupling portions in the tire radial direction RD when viewed from the tire circumferential direction and a second connecting portion region, which overlaps the outer connecting portions of the second coupling portions in the tire radial direction RD when viewed from the tire circumferential direction, and wherein the tread further includes a center portion arranged between the first annular connecting portion region and the second annular connecting portion region of the tread, characterized in that three main grooves extending in the tire circumferential direction are formed in the tread, wherein a first circumferential main groove is formed on the center of the center portion of the tread in the tire width direction WD, wherein a second circumferential main groove is provided in the first annular connecting portion region and a third circumferential main groove is provided in the second annular connecting portion region, wherein only the second main groove and the third main groove located in the connecting portion regions include protrusions individually protruding inward of the groove from both of the groove sidewalls. - an inner annular portion; - an outer annular portion provided concentrically on an outer side of the inner annular portion; - a plurality of coupling portions (3, 31, 32) coupling the inner annular portion and the outer annular portion to each other; - a tread provided on an outer side of the outer annular portion; wherein the plurality of coupling portions comprises a plurality of first coupling portions and a plurality of second coupling portions, which are alternately arrayed with each other along the tire circumferential direction, wherein each of the first coupling portions is extended from one side in the tire width direction of the inner annular portion toward other side in the tire width direction of the outer annular portion and each of the second coupling portions is extended from the other side in the tire width direction of the inner annular portion toward the one side in the tire width direction of the outer annular portion 2, in a way that the first coupling portion and the second coupling portion, which are adjacent to each other, are disposed in a substantially X shape when viewed from the tire circumferential direction, wherein each of the plurality of first coupling portions includes an inner connecting portion (3 1a) connected to the inner annular portion and an outer connecting portion connected to the outer annular portion and each of the plurality of second coupling portions includes an inner connecting portion connected to the inner annular portion and an outer connecting portion connected to the outer annular portion, wherein the tread includes a first annular connecting portion region, which overlaps the outer connecting portions of the first coupling portions in the tire radial direction RD when viewed from the tire circumferential direction and a second connecting portion region, which overlaps the outer connecting portions of the second coupling portions in the tire radial direction RD when viewed from the tire circumferential direction, and wherein the tread further includes a center portion arranged between the first annular connecting portion region and the second annular connecting portion region of the tread, characterized in that three main grooves extending in the tire circumferential direction are formed in the tread, wherein a first circumferential main groove is formed on the center of the center portion of the tread in the tire width direction WD, wherein a second circumferential main groove is provided in the first annular connecting portion region and a third circumferential main groove is provided in the second annular connecting portion region, wherein only the second main groove and the third main groove located in the connecting portion regions include protrusions individually protruding inward of the groove from both of the groove sidewalls.