Provided is a gear material that is for a differential ring gear or the like, and that has a relatively large shape and has spur gear teeth or helical gear teeth at an outer periphery thereof, and with which the yield of a final product is improved, the operating cost of gear cutting by a hobbing machine is reduced, and the rate of cutting is dramatically increased to reduce a machining time, whereby the total manufacturing cost can be reduced. This gear material is in the shape of a ring having an outer diameter of at least 170 mm and an outer peripheral thickness of at least 30 mm, and has, at an outer peripheral surface thereof, spur gear teeth or helical gear teeth with a machining allowance of 0.2 mm to 2.0 mm on either side thereof.