To provide a waste compression/solidification device capable of surely conveying waste such as fibrous cuttings, to a compression chamber 17 within a compression box 19 without accumulating the waste in the vicinity of a delivery port 13 of a hopper 9.

This device is provided with a feed screw conveyor 33 placed inside the hopper 9 and a conveyor motor 35 for rotating the feed screw conveyor 33, wherein the front end of the feed screw conveyor 33 extends at least to a position in the vicinity of the compression chamber 17, the feed screw conveyor 33 is provided with a feed screw shaft 37 the rear of which is connected to the output shaft of the conveyor motor 35 so as to be moved in a linked manner with the movement of the output shaft of the conveyor motor 35 and a conveyor blade 39 spirally formed on the feed screw shaft 37 so as to be wound around the screw shaft 37, and the feed screw shaft 37 is formed so as to be tapered from the rear end side toward the front end side.