A magnetic tape cartridge includes a magnetic tape, and a storage medium in which information on the magnetic tape is stored. The magnetic tape has a recording surface. Data is recorded in the recording surface by a magnetic head in a state in which the magnetic tape is made to travel. The magnetic head is disposed at an inclined posture with respect to a width direction of the magnetic tape along the recording surface. Angle adjustment information obtained before the data is recorded in the recording surface is stored in the storage medium. The angle adjustment information is information for adjusting an angle at which the magnetic head is inclined with respect to the width direction along the recording surface.