A magnetic tape cartridge includes: a magnetic tape on which data is recorded; and a recording medium other than the magnetic tape, and on which a keyword for searching the data recorded on the magnetic tape is recorded.

A magnetic tape device, in which a magnetic tape is caused to run between a winding reel and a cartridge reel in a state where a tension is applied in a longitudinal direction of the magnetic tape and a maximum value of the tension is 0.50 N or more, and the magnetic tape after running in a state where the tension is applied is caused to be wound around the cartridge reel by applying a tension of 0.40 N or less in the longitudinal direction of the magnetic tape, and a curvature of the magnetic tape in the longitudinal direction is 4 mm/m or less.

A magnetic tape cartridge includes: a magnetic tape on which data is recorded; and a recording medium other than the magnetic tape, and on which a keyword for searching the data recorded on the magnetic tape is recorded.