The ozone can sterilize a spore-forming bacteria with a strong oxidation power.Ozone concentration, humidity, sterilization time is an element of sterilization.We revealed in the basic test the ozone sterilization conditions of sport-forming bacteria and general bacteria.We calculated the D value of spore-forming bacteria from this result.High humidity is na important factor of spore sterilization, tests device were placed in a constant temperature bath.Sterilization systems and sterilization conditions in a variety of field is created based on this condition.In the field, the conditions to locate the cold spot of sterilization, can be completely sterilized in this place has been set.Before operation, sterilization confirmation test with spore indicator bacteria was repeated many times.This report is to introduce the actual know-how that were the basic test results and used in the field of the production system.