PURPOSE: To perform a mechanical and automatic dewatering before use of the pallets wet with rain in an open-air storage by providing an air spray device having two air spray nozzle parts at the upper part of a pallet setting device.

CONSTITUTION: A pallet setting device 12, upon reception of a pallet 15 in its groove 14 from a conveyor device, is turned in the vertical direction so as to place the pallet 15 held therein in a standing position, whereby most of the water attached to the back side of the pallet 15 is fallen off therefrom for removal under the force of gravity. At least two air spray nozzle parts 25b are then moved from above and each nozzle part is inserted into a fork receiving opening of the pallet 15, so that the water attached to the inside of the fork receiving opening can be sprayed off therefrom with the air shot out from each nozzle part 25b. The nozzle part 25b is thereafter removed from the fork receiving opening of the pallet 15, the pallet setting device 12 is turned back in the original position and the pallet thus dewatered is removed from the groove.