To improve the productivity of a packaging bags stacking device wherein packaging bags supplied continuously at a given transport cycle on a plurality of transport lines are stacked up to prescribed numbers for respective transport lines.

The packaging bags stacking device comprises: a primary accumulation part wherein the packaging bags supplied from a transport line are stacked up to a primary accumulation number of sheets N1; a secondary accumulation part wherein packaging bags are received from the primary accumulation part while packaging bags supplied from a transport line are further stacked up to a prescribed number of sheets N2; and a packaging bag groups carry-out device which receives the packaging bag groups accumulated at the secondary accumulation part, and while moving them at a given cycle to carry-out positions, carry-out the packaging bag groups to a subsequent process. After stacking of up to a prescribed number of sheets N2 has been made at the secondary accumulation part, packaging bags then supplied from a transport line are accumulated at a primary accumulation part, and while packaging bags are kept accumulated at the primary accumulation part to reach up to the primary accumulation number of sheets N1, packaging bag groups are shifted from the secondary accumulation part to the packaging bag groups carry-out device.