A novel sodium diacetate crystal that has high stability and can suppress the volatilization of acetic acid for a long period of time, more specifically, a sodium diacetate crystal having a median diameter in the range of 300 to 3000 μm.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、より詳細には、300~3000μmの範囲のメジアン径を有する、二酢酸ナトリウムの結晶。