PURPOSE: To expose a cutting blade part only at bringing down the cutting blade part of a cutter so as to execute cutting-off.
CONSTITUTION: In a cutter of which the cutting blade part is moved up and down so as to cut off an object to be cut off, it is provided with cover pieces 12 which are provided on both sides of the cutting blade part 4 of this cutter capably of being opened/closed and have the sizes covering the cutting blade part 4, and belts 14 connecting together the head 1 of the cutter and the vicinity of the lower edge parts of the cover pieces 12, and it is constituted so that a pair of the cover pieces 12 are closed at lifting the cutting blade part 4, and a pair of the cover pieces 12 are opened at bringing down the cutting blade part 4.