To provide a screen apparatus for a papermaking stock which promotes disintegration of the stock to enable an improvement of a yield and a reduction of rejected portion.

A disintegration rotor 25a and a disintegration stator 25b are formed into a tapered shape so that their abutting surfaces incline inwardly (to the side of a rotor 10) as observed from the cross sectional direction. A pocket 26 is formed between the disintegration rotor 25a and the disintegration stator 25b for a foreign matter, which is sent from a screen inlet chamber 6 to the above, to pass through. Pluralities of disintegration teeth are provided on an outer peripheral surface of the disintegration rotor 25a and on an inner peripheral surface of the disintegration stator 25b so that the pluralities of disintegration teeth are on the circumferences at multi-step like in the axial direction. The disintegration tooth has a convex shape on a peripheral surface so as to form a horizontal blade and a vertical blade.