An extreme ultraviolet light generation system is an extreme ultraviolet light generation system which is used with a laser apparatus and is connected to an external device so as to supply extreme ultraviolet light thereto, and the extreme ultraviolet light generation system may include: a chamber provided with at least one inlet through which a laser beam is introduced thereinto; a target supply unit provided to the chamber for supplying a target material to a predetermined region inside the chamber; a discharge pump connected to the chamber; at least one optical element disposed inside the chamber; an etching gas introduction unit provided to the chamber through which etching gas passes, the etching gas being introduced to etch debris of the target material which is emitted when the target material is irradiated with the laser beam inside the chamber and adheres to the at least one optical element; and at least one temperature control mechanism for controlling a temperature of the at least one optical element.