A new method of fructooligosaccharides production was investigated by an amyloglucosidase using sucrose as a substrate. Optimum reaction conditions were as follows: sucrose concentration, 700g/$ell$; pH 5.5; temperature, $55^{circ}C$; enzyme dosage, 48 units per gram sucrose. At the optimized reaction conditions, 41.5% of fructooligosaccharides were produced after 25 hours. A hydrolyzing activity was stronger than transfructosylting activity at low sucrose concentrations, resulting in low production rate of fructooligosaccharides. The optimum pH and temperature in both transfructosylating(pH 5.5, $60^{circ}C$) and hydrolyzing activity(pH$4.75^{circ}C$)were significantly different from each other. The amyloglucosidase also utilized fructooligosaccharides as a substrate and glucose seemed to be an inhibitor.