The problem addressed by the present invention is manufacturing a sugar solution in which the amount of fermentation inhibiting substances is extremely low. The present invention is a method that concentrates an aqueous solution of sugar derived from cellulose using a nano filtering membrane and/or a reverse osmosis membrane and is a method for manufacturing a sugar solution in which an anionic polymer is added and fermentation inhibiting substances are eliminated on the permeated side of a nano filtration membrane and/or a reverse osmosis membrane.
