The present invention provides a rush juice powder which is mainly made from rush containing a high percentage of dietary fiber and having an antibacterial function and an anti-inflammatory function, has an extremely high function to eliminate active oxygen through interaction with a powdered green tea in addition to the original functions of rush, and further is easy to drink. A rush juice powder contains a powdered rush which is made by soaking a rush into the hot water for the blanching treatment, drying the blanched rush by hot-air and then pulverizing the dried rush. Both a powdered green tea and a cyclic oligosaccharide are blended at a respectively determined ratio to the powdered rush.