Patent ID: 7284723

Claim:
A recording tape cartridge comprising: a reel rotatably accommodated within a case, a recording tape being wound around an outer peripheral portion of a reel hub which is formed in a shape of a cylindrical tube having a bottom portion; an engaging portion provided at an inner surface of the bottom portion of the reel hub; a reel gear which is annular, and which is provided coaxially at an outer surface of the bottom portion of the reel hub, and which can mesh with a driving gear of a drive device; a braking member, provided so as to be unable to rotate within the case, able to move to a rotation locked position at which the braking member engages with the engaging portion, and to a rotation permitted position, at which an engaged state with the engaging portion is released by the braking member being away from the bottom portion of the reel hub; a releasing member having a main body portion positioned within the reel hub, and an operation portion provided at the main body portion and exposed, from a position further toward a radial direction inner side than the reel gear at the bottom portion of the reel hub, to an exterior, the releasing member moving the braking member to the rotation permitted position by the operation portion being pushed by a releasing portion of the drive device; a guide portion provided, at the bottom portion of the reel hub, further toward the radial direction inner side than the reel gear; a guide member, provided at the releasing member, for guiding the releasing member in a moving direction along an axial direction of the reel and for impeding rotation of the releasing member with respect to the reel by engaging with the guide portion; and a pass-through hole ( 50 ), formed in an axially central portion of the bottom portion of the reel hub, from which the operation portion is exposed to the exterior, wherein the guide member is an engaging piece protruding from the main body portion toward a radial direction outer side, and the guide portion is a guide groove in which the engaging piece enters, the guide groove being formed at the bottom portion of the reel hub so as to extend in the moving direction and toward the radial direction outer side from the pass-through hole ( 50 ).