Plasma is generated in a gas phase in a processing tub to produce a reforming component, the produced reforming component is dissolved in a liquid and is dispersed in the liquid to produce a reforming liquid, the produced reforming liquid is discharged from the processing tub to be stored in the storage tub, and gas is supplied from a gas supplier into the reforming liquid in the storage tub. The supplied gas has a bubble shape, comes into contact with the reforming liquid stored in the storage tub, and is deodorized.
