To improve the dust collection efficiency by addition of a simple mechanism.

The cutter is used for cutting off the upper side from the lower side, the lower side from the upper side, the right side from the left side and the left side from the right side as to dirt floors, wall surfaces and ceiling surfaces of concrete, block, stone, tile, ALC20 and the like, for chamfering corners and for similar works. In the cutting-off, in forming an incision by the hand cutter that revolves with electricity, air or an engine as a motive power, the cutting groove 2 having, for example, in actual dimensions, a width of nearly 1.5 mm to maximum 12 mm and a depth of nearly 10 mm to maximum 200 mm, is formed with the progress of the cutting, according to the thickness of the cutter blade 31 or the depth of the incision. Most of the dust generated at that time passing the rear scatter-preventing plates 12, 13, located just behind the cutter blade 31, is whirled up toward the dust sucking port 14 and sucked up.