To provide a novel sodium diacetate crystal high in stability and capable of suppressing volatilization of acetic acid for a long time, and a solid dialysis formulation capable of inhibiting volatilization of acetic acid and degradation of glucose and having reduced acetic odor.SOLUTION: A crystal of solidum diacetate is manufactured by a method including following processes: (1) mixing acetic acid and sodium acetate at a molar ratio of 1.5:1 to 1:2； (2) adding water of 0 to 2 wt.% of total weight of the mixture to the mixture； (3) dissolving the mixture by heating at 130 to 250°C after addition of water； and (4) adding a seed crystal after cooling if needed, and cooling them.SELECTED DRAWING: Figure 3【課題】安定性が高く、酢酸の揮発を長期間抑えることができる新規の二酢酸ナトリウム結晶、及び酢酸の揮発及びブドウ糖の分解を抑制でき、酢酸臭が低減された固形透析用製剤の提供。【解決手段】以下の工程を含む方法により二酢酸ナトリウムの結晶を製造する。（１）酢酸と酢酸ナトリウムとを１．５：１～１：２のモル比で混合し、（２）該混合物に、該混合物の全重量の０～２重量％の水を添加し、（３）水の添加後、該混合物を１３０～２５０℃に加熱して溶解させ、（４）必要に応じて冷却後種結晶を添加し、冷却する。【選択図】図３
