PURPOSE: To make bast fiber into a fiber state suitable for ordinary spinning, by arranging alternately plural pairs of lateral channel rollers at least one side of pairs of top and bottom rollers and longitudinal channel rollers and setting draft rollers next to the end rollers.

CONSTITUTION: Plural pairs of the lateral channel rollers B wherein at least one of a pair of the top and bottom rollers 6 and 7 is provided with a great number of the uneven channels 8 on the peripheral surface extended in the shaft direction and the longitudinal channel rollers C wherein a pair of the rollers 10 and 11 is equipped with a large number of the peripheral uneven channels 12 formed along the shaft direction and the rollers engaged vertically are alternately arranged. The draft rollers F and G are set next to the end rollers. Softening degree and dividing degree can be improved.