A space modification apparatus includes a treatment tank configured to generate a gas phase around a rotating center of a rotating flow of a liquid by rotating the liquid, a first electrode of which at least a part is in the treatment tank so as to be in contact with the liquid in the treatment tank, a second electrode in contact with the liquid in the treatment tank, and a power source configured to apply a voltage between the first electrode and the second electrode to generate plasma in the gas phase to generate modification components, the modification components being dissolved and dispersed in the liquid, and a modification liquid being generated and retained in a storage tank. The modification liquid is sprayed or scattered from a nozzle into a treatment target space via a supply pump in the form of mist.