MAGNETIC PARTICLE TESTING DEVICE AND MAGNETIC PARTICLE TESTING METHOD

PROBLEM TO BE SOLVED: To provide a magnetic particle testing device and method for preventing fluorescence of a fluorescent magnetic particle around a conveyed billet from being falsely recognized as fluorescence of the fluorescent magnetic particle adhered on a flaw on the surface of the billet, and ensuring high flaw detection accuracy even if an inclination of the billet surface is changed.SOLUTION: A magnetic particle testing device 1 includes: a magnetization part 2 for magnetizing a testing area; a magnetic particle diffusing part 3 that diffuses fluorescent magnetic particles; an ultraviolet ray irradiation part 4 that makes the fluorescent magnetic particle fluorescent irradiating it with ultraviolet ray; a slit light irradiation part 5 that irradiates positions on the upstream and downstream sides in the conveyance direction of the testing area, with slit light; an imaging part 6; and an image processing part 7. The image processing part 7 corrects the concentration of a pixel group corresponding to the fluorescent magnetic particle in a captured image to a concentration to be obtained when a first inclination angle formed by an ultraviolet ray irradiation direction of the ultraviolet ray irradiation part with respect to a normal direction of the billet surface is changed to a first correction angle and a second inclination angle formed by the imaging direction of an imaging part with respect to the normal direction of the billet surface is changed to a second correction angle, to detect a flaw on the basis of the corrected captured image.