PURPOSE: To prevent lowering of slit precision of a screen even by welding joint of the screen.
CONSTITUTION: Spacer rods 11 are arranged to make a row with specified intervals cylindrically with an outside diameter of a perforated pipe 1 as its inside diameter, wires 12 are spirally wound around its cylindrical outer periphery with specified pitches and ring sleeves 13 are respectively fastened on both ends of the spacer rod 11 on screen jackets 10. Deformed clearance grooves 13A are continuously formed roughly on the center in the thickness direction of the outer peripheral surfaces of the ring sleeves 13, they are welded on the perforated pipe 1 through welded parts 13B on the outside of these deformed clearance grooves 13A, and the screen jackets 10 are welded to each other.