PURPOSE: To improve work efficiency of handling products by storing a plurality of trays in layers in an apparatus body and sequentially supplying and discharging each of stacked trays with a transfer machine.

CONSTITUTION: Stacked trays 20 are stored in a supply portion 2 through an entry portion 18, and one tray 21 of the trays 20 is supported on a transfer guide 8, the other trays 21 being supported by engaging means 7. The trays 21 on the guide 8 is transferred to a product in-and-out portion 3 by a transfer machine 5, and a work robot 40 conducts unloading operation for the tray 21 on the in-and- out portion 3. After operation, the tray 21 is returned to the guide 8 by the transfer machine 5 to be loaded on an elevator 6. When a fixed number of trays are loaded, a carry-out machine 10 discharges the trays from the supply portion to the outside. Meanwhile, the next stacked trays 20 are stored in the supply portion 2, product handling operation is conducted for the trays 21 in the same manner as described above.