A method of removing a carrier plate is used to peel off and remove the carrier plate from a workpiece of a disk-shaped composite substrate in which the workpiece is disposed on a face side of the carrier plate with a temporary adhesive layer interposed therebetween. The method includes a step forming step of forming a step protruding laterally from the carrier plate more on a reverse side of the carrier plate than on the face side of the carrier plate, by removing an outer circumferential portion of the workpiece, an outer circumferential portion of the temporary adhesive layer, and a face-side side of an outer circumferential edge of the carrier plate, a starting point region forming step of forming a starting point region that acts as a starting point in peeling off the carrier plate from the workpiece.