The fluorescent coumarin derivatives of soyasaponin I (1), II (2), III (3), A₁ (4), and A₂ (5) were examined by high performance liquid chromatography (HPLC) and the quantitative determination method for soyasaponin I (1), II (2)+III (3), A₁ (4), and A₂ (5) by HPLC has been developed. By means of this HPLC method, the respective soyasaponin contents in various kinds of soybeans and soybean products have been clarified.