The invention aims at regaining the deodorization performance of a deodorant by decomposing the components of bad smells and harmful gas adsorbed on the deodorant completely in a short time with less labor without generating wastewater. A device (1) for regaining the deodorization function of a deodorant (4) on which at least one of the bad-smelling components and harmful gas components suspended in the air is adsorbed, which is provided with a casing (2) and an active species formation section (3), wherein the casing (2) can hold a deodorant and active species capable of decomposing or deactivating at least one of the bad-smelling components and harmful gas components are formed in the section (3).
