PROBLEM TO BE SOLVED: To make it difficult to introduce air into a sterilization chamber to obtain sufficient sterilizing action by providing a mechanism for removing air, which enters a chamber of a process before a sterilizer is introduced into the sterilization chamber, along with the sterilizer.SOLUTION: The sterilization apparatus for sterilizing the object in the sterilization chamber includes a concentration chamber for concentrating the sterilizer, an evaporation chamber for evaporating the sterilizer, a metering tube in which the sterilizer is charged from the concentration chamber before charged in the evaporation chamber, a vacuum device for evacuating the sterilization chamber and a first valve opened and closed in order to control the continuity of the evaporation chamber and the metering tube. After the sterilizer is charged in the metering tube from the concentration chamber, the first valve is opened to remove the atmosphere contained in the metering tube.
