An extreme ultraviolet light generating device may include a chamber, an EUV light focusing mirror provided therein, including a reflection surface having a concave curved shape and an outer peripheral portion around an outer edge of the reflection surface, and configured to focus EUV light radiated from plasma generated when a target is irradiated with laser light, a gas supplying device including peripheral heads provided on or along the outer peripheral portion; and a discharge device including a discharge path forming a discharge port near the outer peripheral portion, and configured to discharge an ion or a particle from the discharge port. The peripheral heads each may blow out a gas flow from the outer peripheral portion or a vicinity thereof along the reflection surface, and allow gas flows to join on the reflection surface to thereby form a gas flow along the reflection surface toward the discharge port.