[Problem to be Solved]To provide a highly safe and highly effective decontamination device using peracetic acid and a decontamination method employing the decontamination device.[Solution]A decontamination device A for sterilizing an inside of a facility or an inside of a device installed in the facility in which cells, tissues, culture media, sterile reagents, microorganisms or the like are handled or cultured, including: a dry fog generating machine 1, installed in a decontamination area, for converting a peracetic acid mixed solution containing low-concentration peracetic acid into dry fog and spraying the dry fog into the decontamination area； a humidity sensor 3, installed in said decontamination area, for measuring a humidity in the decontamination area； a gas recovery machine 4, installed in said decontamination area, for recovering gas in the decontamination area； and a control device 6 for controlling spraying from said dry fog generating machine 1 and gas recovery operation by the gas recovery machine 4 based on information from said humidity sensor 3, wherein a main control and monitoring device 7, installed outside said decontamination area, for controlling the control devices 6 of one or more of said decontamination devices A is provided.
