Multi-layer grinding stone for gear grinding

Provided is a multi-layer grindstone for gear grinding, which is stable in grinding precision and gear tooth surface roughness during grinding of a finishing grindstone part even in a high-speed rotation region. A multi-layer grindstone for gear grinding has a roughing grindstone part (52) and a finishing grindstone part (54), the roughing grindstone part (52) and the finishing grindstone part (54) are fixed to each other in a state of having a common rotation axis (Cy), and a continuous threaded groove (56) from an outer peripheral surface (52a) to an outer peripheral surface (54a) is formed on the outer peripheral surface (52a) of the roughing grindstone part (52) and the outer peripheral surface (54a) of the finishing grindstone part (54). The finishing grindstone part (54) is formed by laminating grinding cloth (54b), and the elasticity of the finishing grindstone part (54) is higher than that of the roughing grindstone part (52). Thus, even in a high-speed rotation region, it is possible to absorb the di