To provide a manufacturing method and a manufacturing device for manufacturing a ring gear out of a plate stock by using a press.

This manufacturing method comprises a first step of manufacturing an intermediate product with the wall thickness of a necessary part larger than that of a completed product by compressing a unnecessary part which is finally removed in a stock, and moving the material of this part to other necessary parts, and a second step of compressing the part of large wall thickness to obtain the wall thickness of the completed product and cutting and removing the unnecessary part.