Provided is a metal scrap compressor structured in a manner such that exchanging a compression-molding die is easy in comparison to the prior art, and it is possible to avoid scrap accumulation that can be caused by operation faults of a compression cylinder device. A metal scrap compressor, wherein: a compression cylinder device is equipped with a pair of plate-wall-shaped side blocks that form aframe structure by facing one another between a base on a stand and a cylinder flange of a cylinder tube end, and further equipped with a cap-shaped block member having a compression-molding chamberin the interior thereof, and detachably mounted onto the base between the side blocks; and the block member has an opening therein for loading metal scraps, has a press ram affixed to the tip of a piston rod of the compression cylinder device and penetrating through the block member from the ceiling section thereof so as to be capable of sliding back and forth, and has a compression-molding die provided in the interior thereof that is exchangeably mounted to the tip of the press ram and moves back and forth inside the compression-molding chamber.