A recording tape cartridge includes: a reel including a reel hub having an outer diameter of an upper end portion thereof is smaller than that of a lower end portion thereof, and a lower flange in which plural through holes are radially formed and inclined surfaces are formed at one edge portion and the other edge portion of each of the through holes, the inclined surfaces are directed to a flange circumferential direction. An inclination angle with respect to a reel rotation axis of the inclined surface at the one edge portion, which is directed in a rotational direction of the reel, when a recording tape is wound on the reel, is larger than an inclination angle with respect to the reel rotation axis of the inclined surface of the other edge portion, which is directed in the rotational direction of the reel when the recording tape is led out of the reel.

A recording tape cartridge includes a reel including a reel hub having an outer diameter of an upper end portion which is smaller than that of a lower end portion, and including a lower flange in which plural through holes are radially formed. Inclined surfaces, formed at one edge portion and another edge portion of each of the through holes, are directed toward a flange circumferential direction. The one edge portion is directed in a rotational direction of the reel, when a recording tape is wound on the reel. The other edge portion is directed in the rotational direction when the recording tape is led out of the reel. An inclination angle with respect to a bottom surface of the lower flange of the inclined surface at the one edge portion is smaller than that of the inclined surface of the other edge portion.