PURPOSE: To facilitate the discharge of scales and reliably divide flashes by providing notched grooves, with their bottom sections made wide over the whole thickness on the outer periphery of a disk-shaped flash removing cutter pressed to the edge of a traveling plate material and rotated thereby.

CONSTITUTION: A steel plate cut by a milling machine is fed out downstream, with flashes attached on the cutting face. The flash removing face 24 of a flash removing cutter 21 is slantly pressed to the edge with flashes, flashes cut by an outer periphery 29 reach the point 30 of a groove 23 and are applied with a quick direction change and are divided. In this case, if there are multiple grooves 23, the divided length is a factor of several numbers of the peripheral length of the cutter 21, part of the width of the flash removing face 24 is left as a flat face 28, thus no flaws are generated on the surface of a mother material by a cutting section 25 when flashes are removed. Flashes are not made continuously long flashes and are successfully dropped on a scrap conveyor without being stuck to a machine and are reliably divided, with no scales clogged in the groove.