An extreme ultraviolet light generation apparatus may include: a laser apparatus; a chamber provided with an inlet for introducing a laser beam outputted from the laser apparatus to the inside thereof; a target supply unit provided to the chamber for supplying a target material to a predetermined region inside the chamber; a collector mirror disposed in the chamber for collecting extreme ultraviolet light generated when the target material is irradiated with the laser beam in the chamber; an extreme ultraviolet light detection unit for detecting energy of the extreme ultraviolet light; and an energy control unit for controlling energy of the extreme ultraviolet light.