Rotary burrs made of WC-8Co cemented carbide are widely used in automated filing systems, yet rapid cutting-edge wear significantly limits their performance. For this purpose, coupled electromagnetic treatments were applied to the WC-8Co cemented carbide region of rotary burrs to enhance their cutting performance. Four key performance parameters were evaluated: average cutting-edge wear, cutting-head diameter wear, average machining depth, and material removal amount. The cutting performance and the resulting surface roughness of workpieces machined with treated and untreated burrs were compared. As a result, under optimal conditions (0.6 T magnetic field and 1.2 V electric field), coupled electromagnetic treatment reduced average cutting-edge wear and cutting-head diameter wear by 15.4% and 21.4%, respectively, increased average machining depth and material removal amount by 21.3% and 25.2%, respectively, and decreased the surface roughness of the machined workpieces by 36.2%. The study through experimental and numerical analysis confirmed that these enhancements in cutting performance are largely attributed to the increased thermal conductivity and hardness of the treated burrs, which result from reductions in magnetic domain walls and increases in crystal defects induced by the coupled electromagnetic treatment. Such changes collectively suppressed adhesion wear, oxidation wear, and abrasive wear, thereby enhancing the tool's cutting performance.