PURPOSE: To prepare a rice ball at a low cost continuously, by feeding a cooked rice contained in a hopper through a tapered compression chamber to a molding cylinder, and cutting the molded rice to a constant length.

CONSTITUTION: A cooked rice is put into a hopper 1, and then fed into a tapered compression chamber 3 by a screw 2. The cooked rice is compressed and passed through a molding cylinder 4 in such a hard state as to be formed by a hand, and advanced into a molding cylinder 4' to a given length. Springs 7 are compressed by rotating a cam 6 with an independent power 5 to lower a cutter blade 8 to the inside of the gap between the molding cylinders 4 and 4'. Thus, the mass of the cooked rice molded in the molding cylinder 4 is cut to give a rice ball.