Provided is a foreign matter treatment device capable of enhancing the durability of a screen device, preventing any stay of foreign matters, and efficiently and reliably collecting foreign matters in a crushing machine. Arc-shaped screen members 45 are laminated on each other separately in the vertical direction, a rake shaft 47 having a plurality of rakes 46 moving between the screen members is installed eccentrically from a center 45o of an outer circumferential edge of each screen member, a fore-end of each rake is retractable from the outer circumferential edge of each screen member, and the collected foreign matters are scraped proximally by the rakes. Further, a rear side of each arc-shaped screen member is opened, any stay of the foreign matters inside thereof is prevented, the water flow resistance is reduced, and the durability of a screen device 40 is enhanced. Further, an outer circumferential edge of a rotational track of cutter blades is brought close to the outer circumferential edge of each screen members, the fore-end of each rake is retracted from the outer circumferential edge of each screen member to reduce the amount of the foreign matters flowing out downstream between a crushing machine 30 and the screen device 40.