PROBLEM TO BE SOLVED: To provide a method and a device for determining the freshness of mung bean vegetables in a stage where analyte detection by sensory evaluation is difficult.SOLUTION: In a freshness-determining method of mung bean vegetables of the present invention, it is inspected whether or not a grain of a mung bean vegetable contains stachyose, and the detection result is used as a determination index of freshness. Measurement of a stachyose content is performed by a high-performance liquid chromatography method or a thin-layer chromatography method. Further, a freshness-determining device of mung bean vegetables of the present invention comprises: extraction means for extracting soluble sugars contained in the grain of the mung bean vegetable; detection means for detecting stachyose in extracted sugars; determination means for determining the freshness of the mung bean vegetable based on a measured value obtained by the detection means.
