Disclosed is a three-stage millstone including an upper stone having a grain inlet and an inlet path, a middle stone disposed under the upper stone for causing grain, introduced through the inlet path, to move to an edge thereof and grinding the grain using compressive force between the upper and middle stones, a lower stone disposed under the middle stone for secondarily grinding the grain using compressive force between the middle and lower stones, the upper surface of the lower stone being wider than the lower surface of the middle stone and being inclined downward to allow the ground grain to inwardly move from the edge of the middle stone to the center of the lower stone, the lower stone having a grain outlet passage, a rotation device for enabling rotation of the middle stone, other than the upper and lower stones, and an actuator for rotating the middle stone.
