A metal scrap compressor obviates cut scraps accumulation potentially causing malfunction of a press cylinder device. In a metal scrap compressor, a press cylinder device includes: a pair of wall-like side blocks disposed between a cylinder flange at an end of a cylinder tube and a base on a base stand so as to form a frame structure; and a cup-shaped block member removably mounted on the base as disposed between these side blocks and containing therein a pressure forming chamber. The block member includes a charging opening for metal scraps, allows a press ram replaceably mounted to a distal end of a piston rod of the press cylinder device to be reciprocally slidably inserted therein through a ceiling thereof, and includes therein a press forming die replaceably mounted to a distal end of the press ram and reciprocally moved in the pressure forming chamber.