The present invention relates to a tire, particularly, a non-pneumatic tire that has handling performance similar to a pneumatic tire, and supports the load of a vehicle and improve riding comfort by employing a parametric structure. The present invention provides a non-pneumatic tire including a tread 100 that comes in contact with the ground, a rim 300 that is connected with an axle, and a spoke unit 200 that functions as a structural support between the rim 300 and the tread 100, in which the spoke unit 200 is formed by circularly arranging spokes 210, which have a single closed-loop longitudinal cross-section circumscribed to the rim 300, around the center O of the tire.