To prevent clogging even if a mesh size of a screen is set small by forming the screen for collecting the soil sludge in sewage flowing in a water receiving tank in a cylindrical form in which crosssectional trapezoidal bars are arranged with a fixed spacing and the long side is arranged at the inner peripheral side and the short side is arranged at the outer peripheral side.

In a duct collector in which the screen 3 is provided at the lower part of the water receiving tank in which sewage flows from an inflow pipe, and a pressurizing member 4 is performed a reciprocation movement in the screen 3 to press the soil sludge and dehydrate, the screen 3 is cylindrically formed by arranging the crosssectional trapezoid bars 30 with a spacing becoming a mesh size of the screen 3, such that the long side 30a is arranged at the inner peripheral side and the short side 30b at, the outer peripheral side, and both end parts of respective bars 30 are fixed to flanges 31, 32 with welding, etc. A crossectional shape of the bar 30 is set at ≥10 degrees in an opening angle θ of between side faces 30c opposed to an adjacent bar 30c. In order to secure a necessary strength on the bar 30, a ratio H/B between width H and thickness B of the bar 30 is set at ≥3.