Recording tape cartridge

A recording tape cartridge which comprises a bottom section, a top section assembled with the bottom section to form a case body, at least one tape reel accommodated in said case body with a recording tape wound therearound, each of said tape reels having at least one flange with its peripheral edge formed as engaging teeth, an opening defined in the bottom section for allowing entrance of a tape reel releasing member provided on a tape recording apparatus and tape reel braking means for preventing rotation of said tape reel when said recording tape cartridge is not in use, said tape reel braking means comprising a pair of guide wall projections formed at both sides of said opening in said bottom section forming a space therebetween, a stopper member having at least one braking member for engagement with any one of the teeth of said tape reel and being guided by said guide walls so as to move between a first position where said braking member can engage at least one of the engaging teeth of said tape reel for preventing rotation of said tape reel and a second position where said braking member is disengaged from said teeth to allow rotation of said tape reel, means for resiliently biassing said stopper member toward said first position and an engaging means for preventing disengagement of said stopper member from said guide walls in an upward direction.