PURPOSE: To enable the accurate detection of the amounts of unpolished rice and unhulled rice in mixed rice and the mixture ratio between them by a construction wherein a funnel supplying a selecting apparatus with said mixed rice of the unpolished rice and the unhulled rice obtained from a huller is provided with a sensor detecting said amounts.

CONSTITUTION: A mixed-rice funnel 3 supplying a selecting apparatus with the mixed rice of unpolished rice and unhulled rice obtained from a huller is provided with a sensor 4 which discriminates the colors of the unpolished rice and the unhulled rice in the dropping mixed rice by means of a photoelectric tube and detects the amounts thereof. The output of the sensor 4 is delivered to an unpolished-rice counter circuit 17 and an unhulled-rice counter circuit 18 through an unhulled-rice discriminating circuit 16, and in these counter circuits the amounts of the unpolished rice and the unhulled rice are counted. Then the mixture ratio between the unpolished rice and the unhulled rice is calculated accurately by an arithmetic circuit 19. It is also possible to adjust a gap of hulling rolls through a comparator circuit 20, a discrimination reference value 21 and a servo motor 23.