PURPOSE: To cut a sheet metal as the slit product without roducing burrs on the section by a method wherein the sheet metal is precut on both upper and lower sides while leaving part of its thickness and then passed through a zigzag passage.

CONSTITUTION: The sheet metal 1 is precut with the upper cutter 2 and the lower cutter 3, the stepped notches 5 are made by the sections a, b on the upper and lower sides and the sheet metal is connected by the residual portions 4. The precut sheet metal is passed through the zigzag passage 7 of the corrector provided by several rolls 6 that are arranged up and down and by turns, pushed by the rolls 6 and cut by rolling and bending at the remaining portions 4. Accordingly, no warpage, no twist, and no burr are created on the cut sections.