To provide a truer equalizing projection heights of abrasive grains from a matrix in the side faces of a diamond or CBN blade and smoothing surfaces of the abrasive grains to easily eliminate side face runout of the blade, and to provide a side face runout eliminating method using it.

This truer 2 is contacted with the side faces of the diamond or CBN blade 1 and equalizes the projection heights of the abrasive grains from the binding material to eliminate the side face wobble of the blade 1. The truer 2 is made of a composite material formed by including the diamond or CBN abrasive grains in a volume of 5-90% into at least one binding material selected from a metal, a resin, a glass, ceramics or a plating material. By forming a groove 6 in the truer 2 in the direction perpendicular to the rotational axis of the blade 1 and relatively moving the blade 1 in the groove 6 to both the directions of the rotational axis by minute amounts, the projection heights of the abrasive grains in the blade side faces are equalized to smooth the surface of the abrasive grains.