Abstract: A paper cutter particularly one comprising a base, a cutter holder, a blade, a spring wire, an adjusting spring plate, an adjusting knob, an intermediate plate, and a top cover in which a notch is designed at a corner of the base for extension of a blade, the cutter holder is pressed by the adjusting knob with a plurality of protuberances of different diameters to adjust the extent of blade extension for cutting of paper of different thickness without damaging paper beneath it, and the cutting is proceeded by sliding a flange of the base on the paper to assure precise cutting.