PURPOSE:To suppress a rapid magnetic change and to enable execution of eddy-current flaw detection in a temperature range from a Curie temperature to a specific temperature below the Curie temperature by adding a direct-current magnetic field of specific value or above. CONSTITUTION:A direct-current magnetic field by magnetic poles generated in a cylindrical coil group 1 and a housing 2 made of a soft magnetic metal is applied to a material 6 to be inspected which is inserted into the central part of a non-magnetic metal tube 3 provided in the central part of coils and fitting and supporting the coil group 1, and eddy-current flaw detection is executed by a flaw detection coil 5 cooled by water. The coil group 1 is cooled down by making a cooling liquid 4 circulate through a circulation pump. A direct current of about 15A is made to flow through the coil group 1, so that the strength of a magnetic field in the axial direction in the central part be 3000 oersted or above. According to this constitution, execution of the eddy-current flaw detection in a temperature range of a surface temperature from a Curie temperature through 150 deg.C is enabled.
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