PURPOSE: To perform truing of a diamond and CBN grinding wheel in a short time with high precision by using CBN grinding grains for grinding grain, in a truing tool for a super grinding grain grinding wheel.

CONSTITUTION: A super grinding grain grinding wheel to which swing of a grinding wheel working surface occurs and in which a defective shape is formed owing to use is finished in a given shape by a truing tool 1. In the truing tool, CBN(cubic crystal boron nitride) grinding grains 5 are used in the grinding grain thereof and bonded by means of a bonding agent 6 to form a grinding grain layer 4, which is fixed to a base metal 2. This constitution causes finely crushing and wearing of diamond or the CBN grinding grains unevenly protruded from the grinding working surface of the grinding wheel or removes protruding bond material to shape the shape of the grinding working surface. Since the CBN grinding grains are more rigid than GC grinding grains and WA grinding grains, the diamond or CBN grinding wheel can be shaped in a short time with high precision.