A screen device includes a screen dividing a tank into a first chamber and a second chamber for sorting a foreign material in a papermaking material, a first papermaking material supply passage for supplying the papermaking material to the first chamber from the upper side, and a second papermaking material supply passage for supplying the papermaking material to the first chamber from the lower side. The papermaking material passing through the screen is ejected from a middle area of the screen. The screen device also includes an agitating member located inside the first chamber for agitating the papermaking material, and a foreign material outlet passage communicating with the first chamber through a foreign material outlet provided on a side face of the screen. Therefore, the screen device can improve the sorting effect between the foreign material and a good-quality fiber in the papermaking material.