The invention relates to a processing cutter, in particular to a special cutter for processing stepped holes. The special cutter for processing the stepped holes includes a cutter holder and blades; the blades comprise an end processing blade and a radial processing blade; the end of the end processing blade and the end of the radial processing blade are both provided with step-shaped stepped hole processing teeth; the end of the cutter holder is provided with a clamping groove which comprises a first clamping portion and a second clamping portion, wherein the first clamping portion is used for clamping the end processing blade, and the second clamping portion is used for clamping the radial processing blade; the first clamping portion and the second clamping portion are located on the two sides of the axis of the cutter holder respectively, the first clamping portion is located at the position of the diameter of the section of the cutter holder, and the lower end face of the second clamping portion and the upper end face of the first clamping portion are located in the same plane; the end, close to the radial processing blade, of the end processing blade is located at the position of the axis of the cutter holder. The special cutter for processing the stepped holes has the advantages that processing of the diameters of the stepped holes at each stage can be completed at one time, and simultaneous processing of the end faces of the stepped holes and the diameters of the stepped holes can be completed.