A sterilization apparatus characterized in that the sterilization apparatus comprises a reactive oxygen species irradiation unit for irradiating a reactive oxygen species-containing gas which is a reaction product of plasma generated using an alternating current and a water-containing gas containing steam, the sterilization apparatus further containing an inlet unit for steam flow for supplying the water-containing gas heated to a temperature of from 50° to 300° C., wherein the reactive oxygen species-containing gas contains water in an amount equal to or greater than the amount of saturated steam. The sterilization apparatus of the present invention shows excellent sterilization activity, so that it can be suitably used in sterilization of containers for foodstuff, bottle caps sealing the openings of the containers, medical devices, foodstuff such as vegetables and meat, and the like.
