An airless tire comprising: a tread ring having a ground-contact surface ; a hub disposed inward of the tread ring in a tire radial direction and to be fixed to an axle; and a spoke for connecting the tread ring and the hub , wherein the spoke includes a plurality of spoke plates , each of the spoke plates has a first end portion extending in the tire radial direction on one end side in a tire axial direction, a second end portion extending in the tire radial direction on another end side in the tire axial direction, a spoke width (w) measured along a surface of the spoke plate from the first end portion to the second end portion at the same position in the tire radial direction, and a spoke thickness (t) orthogonal to the spoke width (w) and the surface of the spoke plate , each of the spoke plates includes a first curved portion curved so as to project to one side in a tire circumferential direction on the hub side, and a second curved portion curved so as to project to another side in the tire circumferential direction on the tread ring side, as viewed in a direction of the spoke width (w), and an amplitude (a1) of the first curved portion to a reference line between a radial end of the spoke plate in an inner end portion of the spoke plate , which is an end portion on the hub side, and the other radial end of the spoke plate in an outer end portion of the spoke plate , which is an end portion on the tread ring side, and an amplitude (a2) of the second curved portion to the reference line are different from each other, characterized in that a radius of curvature (R2) of the second curved portion is equal to a radius of curvature (R1) of the first curved portion . a tread ring having a ground-contact surface ; a hub disposed inward of the tread ring in a tire radial direction and to be fixed to an axle; and a spoke for connecting the tread ring and the hub , wherein the spoke includes a plurality of spoke plates , each of the spoke plates has a first end portion extending in the tire radial direction on one end side in a tire axial direction, a second end portion extending in the tire radial direction on another end side in the tire axial direction, a spoke width (w) measured along a surface of the spoke plate from the first end portion to the second end portion at the same position in the tire radial direction, and a spoke thickness (t) orthogonal to the spoke width (w) and the surface of the spoke plate , each of the spoke plates includes a first curved portion curved so as to project to one side in a tire circumferential direction on the hub side, and a second curved portion curved so as to project to another side in the tire circumferential direction on the tread ring side, as viewed in a direction of the spoke width (w), and an amplitude (a1) of the first curved portion to a reference line between a radial end of the spoke plate in an inner end portion of the spoke plate , which is an end portion on the hub side, and the other radial end of the spoke plate in an outer end portion of the spoke plate , which is an end portion on the tread ring side, and an amplitude (a2) of the second curved portion to the reference line are different from each other, characterized in that a radius of curvature (R2) of the second curved portion is equal to a radius of curvature (R1) of the first curved portion . <EOS>