The invention is to provide a sheet accumulation apparatus enabling to uniformly load tabbed sheets into a train of sheets for load and store the sheets on a tray. The sheet accumulation apparatus has a sheet outlet for successively discharging the sheets, a tray means for loading to hold the sheets thereon, a sheet carrier means for discharging the sheets from the sheet outlet to the side of a downstream, a sheet front end regulating means for colliding the sheets sent by the sheet carrier means against the regulating means at the sheet front ends and regulating them, and a sheet rear regulating means disposed to the tray means for regulating the positions of the sheets from the sheet outlet at the sheet rear ends. The sheet front end regulating means comprises (1) stopper member movable back and forth in the sheet carrying direction; or (2) stopper means of two or more disposed back and forth in the sheet carrying direction and selectively facing the sheet front end regulating means; or (3) stopper means movable in a direction traversing with carrying along the sheet head ends; a shift means for driving the stopper means; and a control means for controlling the shift means.