A sheet stacking device for stacking conveyed sheets includes a stacking surface on which the sheets are stacked; a plurality of projections that project from the stacking surface. Wherein, the projections extend generally in a travel direction of the sheets, which is a direction in which the sheets travel when entering the sheet stacking device, the projections include outer projections and inner projections, the inner projections are located between the inner projections, and a projecting height of the inner projections from the stacking surface is greater than that of the outer projections.