A paper cutter includes a base having a stationary blade; a fixing seat fixed to the base adjacent to one end of the stationary blade and having a connecting portion extending upward from the base, wherein the connecting portion is atop, peripherally formed with a plurality of teeth, and is formed centrally with a through hole for allowing a shaft to pass therethrough; a connecting element having a rotatory portion that is formed with a slot for allowing the shaft to pass therethrough and being atop provided with recesses for receiving the teeth; and a movable blade having a lower edge formed as a curved edge and having a front end fixed to the rotatory portion. Thereby, when the movable blade is pushed downward, the connecting element is driven to rotate and move along the teeth while approaching and sliding with respect to the stationary blade.