Cellulose has attracted attention as a nonfood feedstock of ethanol. However the decomposition of cellulose is hard because of the strong hydrogen bonding network and the complicated cellulose microfibril structure. 3wt% cellulose was dissolved in 1-allyl-3-methylimidazolium chloride together with 2wt% water, and then gas-liquid interface discharge was carried out for 150 seconds. As a result, the amount of decomposed cellulose reached 6.1%. Total reducing sugar of 4.1% was also produced. The ionic liquid was stable against the discharge.