Abstract: A grinding wheel wear compensator for determining a correct position for a grinding wheel that wears in grinding operation performed on a workpiece so that high grinding accuracy can be ensured.In the grinding wheel wear compensator, in accordance with a desired grinding pattern, a tool centre determining unit determines a tool centre point from a two-dimensional section of the grinding wheel, the section being cut off in an axial direction of the grinding wheel so as to pass its rotary axis and detected by a section detecting unit. Based on the positional difference between the tool centre point determined and a reference point, a wear correction value calculating unit calculates a wear correction value to be used for determining the correct position for the grinding wheel.