a recording tape cartridge houses a reel including a hub around which recording tape is wound and at least part of which is formed by a resin . the rigidity y in the radial direction of the hub and the creep deformation ratio x of the recording tape satisfy the conditions of y ≧ 87 . 3 exp and x & gt ; 0 . 1 . by setting the rigidity of the reel hub to match the creep deformation ratio of the recording tape so as to satisfy this relationship , creep deformation of the recording tape can be controlled at the smallest cost .