PURPOSE: To prevent deterioration of sorting precision by performing regulation on the basis of the detection result of both a detector for detecting the amount of a feed side and a detector for detecting the rate of fluidization.

CONSTITUTION: After husking is allowed to act on unhulled rice, blending rice is scraped up by the potholes of a rotary sorting cylinder 11 rotated to the clockwise direction. Unpolished rice having short grain length falls to a final rice gutter 16 and blending rice of both unhulled rice having long grain length and one part of unpolished rice falls to a feed gutter 14 and is sorted. The unsorted blending rice allowed to fall to the feed gutter 14 is resupplied into the rotary sorting cylinder 11 from the carrier terminal part of the feed gutter 14 by a feed spiral 13 and resorted. Unpolished rice allowed to fall to the final rice gutter 16 is carried to a final rice flow cylinder 17 by a final rice spiral 15. Furthermore, unpolished rice is passed through a grain flow plate 18 for final rice and sorted by sorting wind while it allows to fall to a final rice receiv ing gutter 19 and thereafter is taken out to the outside of the machine by a final rice elevator 20.