PURPOSE: To carry out the transverse traveling and the shiftable operation of a transport dolly through the chain driving outside the transport dolly.

CONSTITUTION: The first driving sprocket 63X which is fixedly installed through a clutch brake 62 on the rotary shaft of a dricing motor 61 installed on a traveling rail is engaged with a transverse traveling chain 70X installed on both the side surfaces of a transport dolly 50. The second driving sprocket 63Y which is fixedly installed on the rotary shaft of a transport dolly driving motor 61 15 engaged with a transport chain 70Y which is negaged with a sprocket 56B on one shaft of a bevel gear unit 55 installed on the transport dolly 50. The sprocket 56A on the other shaft of the bevel gear unit 55 is engaged with the driving chain of a driving conveyor 52 installed on the transport dolly 50.