In this recording media cartridge, a reel around which a recording medium is wound is rotatably received within a case body constituted by coupling upper and lower halves in a face-to-face relationship, the reel is urged toward the lower half by a planar reel presser spring supported on an inner surface of the upper half as in a cantilever, and the reel presser spring is detachably mounted on the inner surface of the upper half, so that the reel presser spring can be collected without damaging components of the cartridge such as the case body, the reel presser spring and a reel lock member. As a result, in this cartridge, the waste materials can be reduced and the impact on the environment can be reduced. The cartridge is effective when different materials are sorted, and the disassembling work can be simplified.