A recording tape cartridge of the present invention includes: a reel formed with an engagement portion on a bottom portion of a reel hub; a resin brake member moving toward and away from the bottom portion of the reel hub, and selectively adopting a rotation locked position and a rotation permitted position; a resin release member being capable of movement in a reel axial direction and rotating as a unit with the reel; and a projection portion that projects out in the reel axial direction from an axial center portion of either the brake member or the release member, that is formed with a housing portion housing a spherical member that contacts the other out of the brake member or the release member, and that is formed with a lip portion jutting out from an opening end portion of the housing portion toward a reel radial direction inner side.