To quickly stack on a pallet a case group aligned in a pattern and supplied from a case supply conveyer with excellent space efficiency, without disarranging an arrangement of cases in a case palletizer.

The case group arranged in a alignment pattern and supplied from a case aligning conveyer is received in a drive roller conveyer device to perform positioning, and is put on a plurality of support plates arranged between rollers by making the drive roller conveyer device descend. In a state in which the case group is put on the support plates, the case group is moved in the perpendicular horizontal direction of the drive roller conveyer device and moved to a stacking position. After an outer periphery of the case group is restricted by a guide, the support plates are returned to a position of the drive roller conveyer device, thereby stacking the case group on the pallet from the support plates.