PURPOSE: To select seed rice containing white-head-threshed rice by forming a swing-up side small outlet which divides a swing-up side outlet in the outlet and attaching an change-over valve to an outlet which is formed in the small outlet and leads outside an apparatus and an outlet which returns to the swing-up side outlet respectively in an apparatus in which the specific gravity swing sorting of grain is conducted.

CONSTITUTION: In a sorting net 5 installed in a swing case 4, the front or back side is made the supply side and the other side is made a discharge side, the right or left side is made the swing-up side 10 and the other side is made a swing down side, a swing-up side outlet 17, a swing-down side outlet 18, and an intermediate outlet 19 are formed outside the discharge side. Angled adjusting bodies 23, 24 are installed between the outlets 17-19 to conduct the specific gravity swing sorting of grain. A swing-up side small outlet 27 which divides further the outlet 27 is formed in the outlet 17, and an outlet 28 which leads outside an apparatus and an outlet which returns to the outlet 17 are formed in the outlet 27. The outlets 28, 29 are opened/closed selectively by a change- over valve 30, and the outlet 29 is closed and the outlet 28 is opened during the sorting of seed rice containing white-head-threshed rice.