To provide an EUV light source of an LPP method and its generating method, capable of greatly enhancing efficiency of using a target material and energy, and capable of restraining generation of debris and degradation of a vacuum degree of a chamber.

The light source includes a vacuum chamber 12 retained in a given vacuum environment, a gas jet device 14 forming a hypersonic steady gas jet 1 of a target material in the vacuum chamber in free recovery, a laser device 16 condensing and irradiating a laser beam 3 to a given condensing point 2 in the hypersonic steady gas jet, and a re-condensing light device 20 reflecting the laser beam 3 which transmits the condensing point, then condensing and irradiating the same condensing point again. The light source generates plasma by exciting the target material by the laser beam 3 at the condensing point 2 to emit extreme ultraviolet light 4 from there.