PURPOSE: To reduce propulsion driving forces and enhance the operability, traveling performance and safety of a device by using plural sets of expansion propulsion devices to continuously move heavy articles slidably supported on a slide way.

CONSTITUTION: Just before an expansion type movement propulsion device B ie. one of a plurality of expansion type movement propulsion devices for moving heavy articles 10 slidably supported on a slide way 25 completes its driving stroke, the other non-load expansion type movement propulsion device A is clamped to the slide way 25 while being actuated to expand or contract so that the driving subject 21 is transferred, thereby continuously conveying the heavy articles 10. This method permits propulsion driving forces to be smaller compared to in the case of conveying heavy articles by means of intermittent action between movement and stopping, so that both the operability and travelling performance of the device are enhanced and also the safety is enhanced.