Gears used for elevators of high story apartments and office buildings require highly accurate design, process and precision. Studies and improvements are made so that tooth form can be optimized by using CNC hobbing, CNC worm cutter and CNC grinder, and gears are manufactured after data is accumulated for each type. Wormgears with capacity up to 37 kW are produced. Not only the K, I, N, A and C type tooth forms but also arbitrary tooth form can be processed.