Measuring method and measuring apparatus, exposure method and exposure apparatus

摘要: An object is to provide a measuring method and apparatus having excellent working efficiency, which can measure an optional substance contained in predetermined gas accurately promptly, exposure apparatus. S comprises; section M capable of absorptive substance, supply unit N GS optical path space LS the M, clean H GT 2 has been reduced, switchover device B switch 2, M. Measurement concentration performed state where residual reduced.