A method for sterilization according to the present invention comprises: a first sterilization step of providing a sterilization subject in a sealed sterilization chamber and sterilizing the sterilization subject by providing ozone inside the sterilization chamber a first decomposition step of decomposing the ozone inside the sterilization chamber a first vacuumization step discharging the gas inside the sterilization chamber and reducing the pressure inside the sterilization chamber a second sterilization step of providing hydrogen peroxide into the vacuumized sterilization chamber to sterilize the sterilization subject a third sterilization step of providing ozone into the sterilization chamber a second decomposition step of decomposing the hydrogen peroxide and ozone inside the sterilization chamber and a second vacuumization step of discharging the gas inside the sterilization chamber and reducing the pressure inside the sterilization chamber.
