The optimum conditions for springiness of polymannuronate acorn mook, in which polymannuronate was added to acorn powder, was investigated by the response-surface method(RSM). The fractional factorial design with three variables, i.e. polymannuronate addition, water addition and boiling time, and with three levels revealed that the range of acorn springiness was $0.804{sim}0.987$. The governing equation was also partially differentiated for boiling time, showing that the optimum manufacturing condition for $90^{circ}C$ is addition of 2% polymannuronate, addition of 120 mL of water, and 60 minutes of boiling time.