A straight fixed cutter is mounted on a frame, a movable cutter carrier slidably supported on the frame to be moved along the fixed cutter. A movable cutter having a disc shape is rotatably mounted on the carrier, and contacted with the fixed cutter. A movable cutter rotating roller is rotatably mounted on the movable cutter carrier and resiliently contacted with the fixed cutter. An endless belt is provided in the frame along the fixed cutter, and connected with the movable cutter carrier. The movable cutter carrier is moved by the endless belt, and the movable cutter is rotated along the fixed cutter to cut a paper sheet mounted on the fixed cutter.