Cellulose prepared from beech wood (Fagus crenata Blume) was treated in a corona discharge. The chemical changes produced by the treatment were investigated by use of infrared spectrum, Schiff's reaction, adsorption of methylene blue and Orange II, and intrinsic viscosity. Infrared absorption bands at 1382 and 1715 cm−1 were formed. The color reaction with Schiff's reagent indicated that the 1715 cm−1 absorption was due to the aldehyde group and not to the carboxyl group. The intrinsic viscosity was decreased by the air corona treatment, but was not affected by nitrogen corona treatment. The adsorption of methylene blue was not increased by corona treatment, indicating that no acidic groups were formed. Adsorption of Orange II indicated that some basic groups were formed by the nitrogen corona after a long treatment time. Low molecular weight fractions showing the 1382 cm−1 infrared absorption band were formed by corona treatment. These fractions were removed from cellulose by washing with water, and they increased with an increase in the treatment time. The absorption band at 1382 cm−1 was assigned to the symmetric carbon-hydrogen bending of methyl group.