PURPOSE: To take out as a rod-shaped solid by providing a perforated plate at the end and the middle parts of an extruder housing an extruding screw.

CONSTITUTION: A connecting casing 2 is connected to one end of the first cylinder 1, and one end of the second cylinder 3 is connected to the bottom of the connecting casing 2. A connecting casing 4 is connected to the other end of the second cylinder 3, and one end of the third cylinder 5, which is installed horizontally, is connected to the bottom of the connecting casing 4 at right angles to the second cylinder 3. The cylinders 1, 3, and 5 and the connecting casings 2 and 4 constitute an extruding cylinder and a pressure reducing chamber. Screws 6, 7, and 8 are provided to the cylinders 1, 3, and 5. The material to be treated is thrown into the cylinder 1 from a hopper 9 provided to the upper side of the cylinder 1, and passed successively through the cylinders 1, 3, and 5. Perforated plates 11, 12, and 13 are provided to the opening parts of the cylinders 1, 3, and 5 on the discharge side.