Recently, improvement of eggshell hygiene has emerged as an important issue in food industry. Various studies have continued to examine methods for controlling egg-borne pathogen, and among such methods, for table eggs, washing (with UV irradiation) is the most commonly used method. However, this method was not sufficient to control egg microbial contamination. Therefore, the purpose of this study was to verify whether it is appropriate to use ClO2 gas, which has been proven safe in this experiment model, as an alternative to the conventional washing (with UV irradiation) method. As a result, we have identified a range of optimal effectiveness in response to exposure concentrations and time of ClO2 gas. Through experimental models that reflect differences in farm size, a microbial reduction effect of approximately >2 log CFU/eggshell was achieved at 40ppm/8h for small farms, and 160ppm/30min for large farms, indicating greater effectiveness than the conventional method. However, in large-scale experiment, when bulk eggs were stacked and exposed to ClO2 gas, eggs in the depths showed a lower effect by approximately 0.8~1.5 log CFU/eggshell, as compared to the eggs in the upper section. For further study, if technical improvements are achieved in the future studies allowing the gas to better penetrate the depths of stacked eggs, it will be a model that can be more useful to the field.