This study was investigated the optimal time that enhanced the functional activities of mung beans for use of functional food resources. Mung beans were roasted according three levels of roasting time levels (10, 20 and 30 minutes) at $110^{circ}C$ and then the physicochemical compositions were determined. The reducing sugar content was decreased with the increased roasting time. Moisture was decreased with increased roasting time, whereas, crude fat, crude ash, crude protein and carbohydrate were increased with prolonged roasting time. The highest contents of total phenol and flavonoid were shown at a roasting condition $110^{circ}C$ for 30 minutes. The highest inhibitory activities of DPPH radical, ABTS radical and xanthine oxidase was the best at the condition of $110^{circ}C$ for 30 min. From these results optimal roasting time of mung beans were 30 minutes for use of functional food resources.