PURPOSE: To prevent the abrasion of hulling rolls by a method wherein the hulling rolls are continuously operated while the gap therebetween set during the execution of control is kept during a surplus operating time even when the supply of unhulled rice being a raw material is stopped earlier than a preset operating time.

CONSTITUTION: A microcomputer is equipped with an operating time setting mechanism for presetting an operating time T and hulling treatment is performed during said operating time while a pair of hulling rolls 24, 25 are rotationally driven. Further, a roll gap control means for performing cooperative control so as to make the gap (l) between a pair of the hulling rolls wide and narrow is provided and a control execution time setting means for performing the gap control of the dehulling rolls only for the short time (t) set within the range of the above mentioned operating time is provided and a holding means for continuing operation during a surplus time while keeping the set gap between the hulling rolls during the execution of control is provided. As a result, the mutual contact of the hulling rolls is not brought about during the surplus operating time and the abrasion of said rolls is not generated.