To provide 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 crusher.

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 45 is installed eccentrically from a center 45o of an outer circumferential edge of each screen member 45, a fore-end of each rake 46 is retractable from the outer circumferential edge of each screen member 45, and the collected foreign matters are scraped proximally by the rakes 46. Further, a rear side of each arc-shaped screen member 45 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. A water flow guide unit 50 capable of forming a flow of water to be treated toward a crusher 30 is provided before the position at which the rotating rakes 46 are directed to the crusher 30 toward the directed position so as to allow the foreign matters to be easily separated from the outer circumferential edge of each screen member 45.