PROBLEM TO BE SOLVED: To provide an effervescent composition for carbon dioxide bath agent in which organic salt and carbonate exist together in combination with inorganic salt hydrate, while its excellent storage stability can be exerted.SOLUTION: According to the present invention, there is provided an effervescent composition for carbon dioxide bath agent, the composition comprising: following components (A), (B), (C), and (D): (A) organic acid: (B) carbonate； (C) inorganic salt hydrate in amount of 1% by mass or more and 20% by mass or less； and (D) polyethylene glycol having an average molecular weight of 1500 or more and 20000 or less. In the composition, the mass ratio ((C)/(D)) of the component (C) and the component (D) is 0.05 or more and 0.9 or less. Furthermore, the composition comprises one or two of granules selected from a granulated product X containing the component (A) and the component (D) and a granulated product Y containing the component (B) and the component (D).SELECTED DRAWING: None
