The sterilization of the microorganism by ultrasound is due to OH radical and shock wave caused by ultrasonic irradiation in water. In this work, the growth activity of the Saccharomyces cerevisiae (yeast) and Escherichia coli XL1-Blue (E.coli) and by sonication with various frequencies(24, 168, 200, 1500kHz) was investigated. In order to evaluate the growth activity of the sonicated yeast cells and E.coli, the formation of the nucleic acid during the growth in the culture medium and permeability of the cell membrane were analyzed by flow cytometry. As a result, the inactivation effect of ultrasound on yeast cells was the largest at 24kHz, where the yeast cell was inactivated mainly by shock wave. On the other hand, the effect of OH radicals is large at 168 and 200kHz.