Provided is a production method for fructooligosaccharide, characterized by having a dissolved oxygen content of 2-8 ppm in a reaction step in which [beta]-fructofuranosidase is caused to act on sucrose and a fructooligosaccharide is produced, and glucose being a by-product of said reaction is reduced by glucose oxidase. As a result of this method, fructooligosaccharide can be produced inexpensively and efficiently.
