To provide a method capable of visually evaluating a magnetization distribution over a magnetic thin-film such as a ferromagnetic shield layer of a device like a GMR head.

By using the evaluation sample including materials 22 and 23 for preventing magnetic field leakage, disposed adjacent to magnetic materials 21, 24 and 25, the evaluation is performed by examining a magnetic domain distribution of the magnetic material via electron-beam holography. Specifically, the device evaluation is performed by entering an electron beam into the sample in the direction perpendicular to the cross section in which the magnetic domain distribution of the magnetic material is to be examined, thereby sensing a distribution of phase change of the electron beam passing through the sample under the condition that a phase shift of the electron beam formed within the inducing material adjacent to the magnetic material is minimized, thus determining the magnetization distribution in the magnetic material.