Abstract: Provided is an inexpensive and efficient saccharification method for woody biomass and a method of producing ethanol from woody biomass. A method for saccharification of woody biomass comprising hydrolysis treatment and an enzymatic treatment, in which a pretreatment process is performed prior to the enzymatic treatment and said pretreatment includes the steps of: hydrolyzing woody biomass, separating the resultant reaction product into a primary sugar solution and a residue, mixing the residue with an aqueous alkaline solution, and mixing with an oxidant capable of generating active oxygen.