A magnetic tape cartridge includes a reel around which a magnetic tape is wound, a cartridge case rotatably accommodating the reel, a reel lock for locking rotation of the reel relative to the cartridge case, a resilient member urging the reel lock toward the reel, a release pad for disengaging the reel lock by displacing the reel lock against an urging force of the resilient member, so as to allow rotation of the reel, and a pivot provided on the reel lock at a position facing with and slidably contacting a contact surface of the release pad in a manner allowing rotation of the release pad. The pivot and the contact surface are both made of resin, and the contact surface is made of a resin having a higher hardness than the pivot.