To provide a tray stacking device, and a method of exchanging the stacked trays using the device capable of totally changing or exchanging one part or all of multiple stages of stacked trays while maintaining the order of stack by preventing concentration of loads at a limited portion.

In this tray stacking device 1, a plurality of pawls 5 aligned in a height direction on each one side of holder units 2, 3 are engaged with a plurality of stacked trays 21, so that a plurality of the trays 21 are held by the holder units 2, 3 via the pawls 5. When the holer units 2, 3 are raised under this holding condition, a plurality of the pawls 5 disperse and support loads of the trays 21. The sequential trays 21 raised by rising the holder units 2, 3 can be totally exchanged while maintaining a stacking condition by moving the trays with an appropriate means, or moving a transfer means arranged below the holder units 2, 3, then lowering the holder units 2, 3, and releasing engagement with the trays 21.