PROBLEM TO BE SOLVED: To provide a water-soluble preservative composition which has characteristics such as comprising synergistically acting multiple active ingredients, decreasing human and environmental exposure and contamination, allowing cost reduction, and hardly causing shock or the like when added to water-based industrial products.SOLUTION: The water-soluble preservative composition comprises, as active ingredients, (A) 2-methyl-4,5-trimethylene-4-isothiazolin-3-one, and at least one compound selected from among (b) 2-methyl-4-isothiazolin-3-one, (c) compounds represented by formula (1), and (d) compounds represented by formula (2).SELECTED DRAWING: NoneCOPYRIGHT: (C)2020,JPO&INPIT【課題】複数の有効成分が相乗的に作用し、人、環境が被曝して汚染される程度が減少し、コスト削減が可能であると共に、水系工業製品に添加した際、ショック等を起こしにくい等の特徴を有する水溶性防腐剤組成物の提供。【解決手段】（Ａ）２－メチル－４，５トリメチレン－４－イソチアゾリン－３－オンと、（ｂ）２－メチル－４－イソチアゾリン－３－オン、（ｃ）式（１）によって表される化合物、及び（ｄ）式（２）で表される化合物から選択される少なくとも１種の化合物と、を有効成分として含有する、水溶性防腐剤組成物。【選択図】なし
