PURPOSE: To make it possible to polish rice efficiently with a little amount of water without producing crushed grains by rotating an erected screw and a rotary rice stirrer and polisher in a rice washing tub shaped in a cylinder in the upper part and an inverted truncated cone in the lower part, so that rice grains are pressed against the slope of the inverted truncated cone part and frictioned one another in revolution caused by differences of the rotation of a stirring vane.

CONSTITUTION: After a desired amount of rice is thrown into a rice washing tub 1, water of a substantially same amount at volume ratio as the rice is supplied from a water supply tube 15, with the water level substantially as high as the rice level. When a screw 2 and a rotary rice stirring and polishing means 4 rotate in direction A, rice grains ascend due to the rotation of the screw 2 from the central bottom of the tub 1. Then the rice grains are pushed in the centrifugal direction (indicated by arrow B) by the rotation of a stirring vane 3 toward the outer periphery within the tub 1, and then descend in a swirling streamline to the bottom of the tub 1. The rice grains are transferred again upward and thus repeat a convection circulation within the tub 1. In this motion, when the rice grains are pressed against the sloped surface of the rice washing tub 1 by the stirring vane 3, rice bran and other foreign elements attached in the recessed parts of the rice grains are peeled off. If a little amount of water is added from the water supply 15, they flow out through an overflow pipe 16.