The present invention provides a grinding stone in which multiple vitrified bonded grindstone tips are disposed on the circumference of an annular base metal and which grinds a workpiece with said grindstone tips while rotating the annular base metal. The grinding stone is characterized in that: the vitrified bonded grindstone tips are rectangular solids that have a rectangular grinding surface, which is located on the side opposite the annular base metal and is for grinding the workpiece, and four side surfaces adjacent to said grinding surface, wherein the four ridges between the side surfaces are chamfered; the long sides of the grinding surface are disposed so as to follow the circumference of the annular base metal; and for the four ridges, at least 1/5 of the length of the short sides of the grinding surface is chamfered. Provided thereby is a grinding stone that is not damaged during grinding and that, with a simple shaping, is capable of limiting extreme damage of the workpiecedue to excessive cutting towards the center of the workpiece.