INSPECTION SYSTEM

PROBLEM TO BE SOLVED: To detect a metal foreign substance mixed in an object to be inspected which is a sheet-like magnetic material at high speed and with high accuracy.SOLUTION: The present invention relates to an inspection system 1a which inspects whether or not the metal foreign substance is mixed in a material 111 to be inspected which is the sheet-like magnetic material, the material 111 to be inspected with a possibility of containing the metal foreign substance is magnetized, after that, a magnetic field with intensity for canceling magnetization of the material 111 to be inspected is applied to the material 111 to be inspected, difference processing is performed to magnetic signals detected by a plurality of magnetic sensors 130 to determine whether or not the metal foreign substance is mixed in the material 111 to be inspected based on a result of the difference processing.