A package accumulating device is disclosed. The device conveys bag packages to a predetermined position while performing an accumulating operation that aligns the packages such that parts of each of the packages lie on top of parts of adjacent packages in a thickness direction. The device includes first and second conveyors, and a control unit. The first conveyor performs the accumulating operation. The second conveyor conveys a group of the packages aligned by the first conveyor. The control unit performs switching between a first state where a downstream end of the first conveyor and an upstream end of the second conveyor oppose each other when the second conveyor accepts the group of the packages from the first conveyor and a second state where a position of the upstream end of the second conveyor is lower than in the first state with respect to the downstream end of the first conveyor.