A cutting apparatus and a cutter of a cutting apparatus for a screen protector. The cutting apparatus includes a carrying machine, a displacement mechanism, a processing module, and a cutter. The displacement mechanism is assembled to the carrying machine and is movable relative to the carrying machine. The processing module is assembled to the carrying machine. The processing module is electrically coupled to the displacement mechanism and is configured to move the displacement mechanism along a hole cutting path and a screen cutting path that is different from the hole cutting path. The screen cutting path corresponds to a contour of a screen of a mobile apparatus. The cutter is assembled to the displacement mechanism. The cutting apparatus can perform a cutting process to a universal sheet through the cutter thereof, thereby forming a screen protector.