PURPOSE: To make it possible to utilize a pallet as an idle station where said pallet is transferred from a workpiece arranging position or a station onto a carriage, by leaving the carriage at an intermediate position between said position and a processing station.

CONSTITUTION: A carriage 3 reciprocating between a workpiece arranging position 1 and a prcessing station 2 travels from a pallet replacing point to the processing position 2 through operation of an actuator. An endless chain 9 begins to run from a pinion 10 obtaining a rotary force by the travel of the carriage via a clutch 12, an accelerating mechanism 13 and a sprocket 7. When the actuator is operated to recover its original position, the pallet 17 moves more rapidly than the carriage 3 and stops temporarily to be on standby at a central position between the workpiece arranging position 1 and the processing station 2.