PURPOSE: To prevent burrs from being produced when the end portion of a thin steel sheet is cut by side trimmers, in a side trimming method free from burrs for thin steel sheets.

CONSTITUTION: A thin steel sheet is cut to a specified depth by side trimmers 1 and 2 provided with a pair of rotating round blades, leaving the uncut portions at both ends. Then the cut portion is held between and pressed by a pair of upper and lower cylindrical rolls 3 and 4 to cut off the sheet at the uncut portion.