An extreme ultraviolet light generation system includes a target supply unit configured to supply a target substance to a first predetermined region, a laser system configured to output pulse laser light to be radiated to the target substance in the first predetermined region, a first sensor configured to detect an arrival timing at which the target substance has reached a second predetermined region between the target supply unit and the first predetermined region, an optical adjuster arranged on an optical path of the pulse laser light between the laser system and the first predetermined region, and a processor configured to control transmittance of the pulse laser light through the optical adjuster based on the arrival timing.