Abstract: Sizing screen apparatus is provided with mechanism for enabling the extent of spacings, longitudinally of an elongate sizing screen between transversely extending, individual rows of spacing members, to be adjusted individually. Each transversely extending row of sizing members is mounted on a rotatable shaft journaled at its opposite ends in the lower end portions of a pair of mounting arms that are pivoted at their upper end portions to opposite longitudinal side members of a supporting frame and hang downwardly for back and forth space adjusting movement. The mounting arms of the pair are pivotally interconnected adjacent their lower ends with an elongate connection member of an operating device that is manually or power operated.