A method for effectively absorbing and removing CO.sub.2 in an exhaust gas generated during an industrial process for reducing the amount of CO.sub.2 that is exhausted into the atmosphere. The exhaust gas containing CO.sub.2 is blown into an agglomerate of solid particles containing CaO and/or Ca(OH).sub.2 so that the CO.sub.2 is in contact with the agglomerate for fixing the CO.sub.2 in the exhaust gas as CaCO.sub.3, thereby reducing the CO.sub.2 concentration in the exhaust gas. Preferably, the solid particles contain water, and more preferably, the solid particles contain surface adhesive water.