Abstract: A measurement method is provided for non-destructive inspection of a magnetic material as an inspection target in a non-magnetic body. The method includes application of a magnetic field from a magnetic field applying unit to the inspection target through a surface of the non-magnetic body, and measurement of a magnetic field from the inspection target with a magnetic sensor on the surface of the non-magnetic body adjacent to the magnetic field applying unit at positions having different distances from the magnetic field applying unit in a first direction away from the magnetic field applying unit. The magnetic field from the inspection target is attenuated with the distances. In the method, first and second measurements are performed with the magnetic field applying unit respectively arranged on one side and on the other side in the first direction relative to the positions where the magnetic sensor performs measurement.

Abstract: A packaging structure for packaging roll-shaped materials wound on a core, comprises: a bottom plate; left and right supporting plates to support both end portions of the core from a bottom side of the core; front and rear holding plates to support the left and right supporting plates from front and rear sides of the left and right supporting plates so as to hold a stand-up condition that the left and right supporting plates stand on the bottom plate; and a supporting structure to make the bottom plate, the left and right supporting plates and the front and rear holding plates in a single body structure and to make the left and right supporting plates and the front and rear holding plates collapsible.