PURPOSE: To enable the inspecting of work automatically and efficiently, by placing the work on a pallet with a relay block to connect the work airtight with the relay block.

CONSTITUTION: As a closed circuit is formed with a conveyor 1 to run a pallet 6, the pallet 6 is used in circulation by loading or unloading work 7. On the upstream of an inspecting machine 2, the work 7 is supplied with a feeder 3 to be placed on the pallet 6 and on the downstream of the inspecting machine 2, the work 7 is carried out with a carry-out device 4. A connecting member 9 of the pallet 7 is linked to a relay box 11 through a piping in the pallet and a connecting block 12 on the side of the inspecting machine 2 is automatically joined to the box in the machine. A connecting member (head) 10 is mounted at the tip of the member 9 and the tip thereof is linked to a pipe 8 of the work 7 and hence, the use of the heads 10A... to match the number thereof in the corresponding size enables inspection of multi-kinds of work. This also permits quick and effective inspection as the pallet is transferred with a conveyor.