An active species radiation device is for efficiently radiating active species (active oxygen or nitrogen) by using a plasma source not in contact with an irradiated object. An active species radiation device (100) includes: a chamber (110) in which flows of plasma generation gas and active species generation gas enter and which has an active species radiation port (110c) through which active species are radiated an upstream electrode (120) positioned in a part of the chamber (110) corresponding to an upstream portion of the flow of the plasma generation gas and a downstream electrode (130) positioned in a part of the chamber (110) corresponding to a more downstream portion of the flow of the plasma generation gas than the upstream electrode (120). The chamber (110) is configured so that the active species generation gas flows into a position between the upstream electrode (120) and the active species radiation port (110c).
