To provide a device and a method for grooving an electrical steel sheet, by which a uniform groove shape is formed easily on the surface even when the sheet thickness of an electrical steel sheet is varied.

The device for grooving an electrical steel sheet includes: a reference pressing roller 8, a grooving roller 9 and a reference pressing roller 10 in the traveling direction of the electrical steel sheet. The reference pressing rollers 8, 10 press the surface of the electrical steel sheet 6 by their outer peripheral surfaces and, on the grooving roller 9, a grooving projection 9a is formed on its outer peripheral surface. The grooving is performed after adjusting the position of the grooving roller 9 so that the height of the projection 9a formed on the grooving roller 9 is projected by a predetermined amount than the height of the outer peripheral surfaces of the reference pressing rollers 8, 10.