A study was carried out to get fundamental informations on the production of ammonium carbonate solution whose concentration is suitable for producing ammonium sulfate by chemical absorption of ammonia and carbon dioxide into water in a bubble column. Two reactant gases were simultaneously absorbed in the bubble column, and the rates of absorption of the gases were determined by chemical analyses of liquid leaving the bubble column after a sufficient time for a steady state to be reached. The experimental results agreed well with the results of numerical solution for the case of pseudo first-order reaction, and the ammonium carbonate solution of 34.1 wt%, which would be suitable for producing ammonium sulfate from its reaction with gypsum, could be easily obtained by the chemical absorption in a bubble column.