A device for removing toxic or harmful materials from an inside sealed by a sealed-type flexible enclosing cover, wherein the contaminated surface of the subject of decontamination is covered with the enclosing cover and a reactive gas is introduced thereto, and particularly to a decontamination and sterilization device, wherein a plasma generator is fixed to a enclosing cover and a plasma gas containing an active radical generated from the plasma generator is introduced to the inside sealed by the enclosing cover together with a reactive gas having a hydroxyl group such as hydrogen peroxide (H2O2), water (H2O), or an alcohol (CnH2n+1OH) to thus increase the production of a reactive radical, whereby the plasma and the reactive gas are intensively applied to the inside sealed by the enclosing cover, thus increasing the contact with contaminants and realizing more efficient decontamination.
