PROBLEM TO BE SOLVED: To provide a granular bath agent composition affording a sufficiently high gaseous carbon dioxide concentration, and having good preservation stability.SOLUTION: The granular bath agent composition comprises following ingredients (A) to (C): (A) 25-55 mass% of an alkali metal carbonate in which &ge50% of particles have &ge180 &mum particle diameter, (B) 40-70 mass% of an organic acid in which &ge50% of particles have &ge180 &mum particle diameter, and (C) 0.01-10 mass% of a slightly water-soluble metal oxide.COPYRIGHT: (C)2009,JPO&INPIT【課題】十分に高い炭酸ガス濃度が得られ、保存安定性の良好な粒状浴用剤を提供する。【解決手段】次の成分(A)~(C):(A)粒子径が180μm以上の粒子が50%以上である炭酸アルカリ金属塩 25~55質量%、(B)粒子径180μm以上の粒子が50%以上である有機酸 40~70質量%、及び(C)難水溶性金属酸化物 0.01~10質量%を含有する粒状浴用剤組成物。【選択図】なし