A processing system according to the present invention is provided including: an adsorption apparatus in which a volatile organic compound contained in gas to be treated is adsorbed in a predetermined absorption agent, and said volatile organic compound thus adsorbed is desorbed using steam under a pressurized environment and mixed with the steam; a gas turbine having a combustor in which the steam mixed with the volatile organic compound is burnt; and a steam generating apparatus which generates steam through the use of the heat of the combustion gas discharged from the gas turbine; and wherein, by supplying compressed air discharged from the gas turbine to the adsorption apparatus, condensation of the steam in the adsorption apparatus at the time of the desorption of the volatile organic compound is suppressed.