Provided is a method of measuring a magnitude of magnetization of a perpendicular magnetic thin film, including: forming a stripe pattern in which a first magnetic domain that extends in a y direction and is magnetized in a z direction and a second magnetic domain that extends in the y direction and is magnetized in a direction opposite to the z direction are arranged alternately in an x direction, in a perpendicular magnetic thin film that extends in an xy plane; changing widths in the x direction, of the first and second magnetic domains by applying a magnetic field having a predetermined magnitude, in the z direction, to the perpendicular magnetic thin film; and calculating an absolute value of the magnetization of the perpendicular magnetic thin film on the basis of a ratio between the widths in the x direction, of the first magnetic domain and the second magnetic domain.