Quick and inexpensive determination of an aggregate of point defects in a grown silicon semiconductor single crystal bar is accomplished by a method which comprises cutting a wafer from a freshly grown silicon single crystal bar, etching the surface of this wafer with the mixture of hydrofluoric acid and nitric acid thereby relieving the wafer of strain, treating the wafer with the mixture of K.sub.2 Cr.sub.2 O.sub.7, hydrofluoric acid, and water thereby giving rise to pits 2 and ripple patterns 1 therein, determining the density of the pits 2 and that of the ripple patterns 1, and rating the aggregate of point defects by virtue of the correlation between the densities of the pits 1 and the ripple patterns 1 and the aggregate of point defects.