To provide a disc-shaped grinding wheel which can attain longevity by suppressing a base material from being chipped off by deposited and solidified grinding sludge.

This disc-shaped grinding wheel, which is formed by attaching a grindstone layer 4 at the top surface of a roughly disc-shaped base material 2, is provided with an adhesive layer 4 which involves a main body part 4a having its top surface allowed to abut to an object to be ground, and an extended part 4b formed so as to be extended downward in a wheel axial direction X along the outer periphery side surface of the base material 2 from the main body part 4a. A plurality of the extended parts 4b are disposed at equal intervals in the, circumferential direction. The abrasive layer 4 is formed by using a vitrified bond grindstone which includes diamond superabrasive grain or cubic boron nitride super-abrasive grain.