PURPOSE: To provide a crushed piece compressing device which is simple in structure, quick in processing speed, excellent in working efficiency, and easy in handling.

CONSTITUTION: Crushed pieces 5 entering a casing 3 through a crushed piece introduction port 7 formed in the upper part of the casing 3 is conveyed downward by means of a spiral plate 6 rotated togetherwith a rotary shaft 4. Since the pitch of the spiral plate 6 is gradually decreased toward below, the crushed pieces 5 are pressed downward as they are conveyed, and an apparent volume is reduced. The crushed pieces 5 conveyed to a discharge port 8 are discharged in a recovery container 12, set right below the discharge port 8, in a way that when a pressure from above exceeds to a value higher than the force of a spring 10 of a door 9, the door 9 is forcibly depressed for opening. In this case, the apparent volume of the crushed pieces 5 is sharply reduced by means of pressure.