PURPOSE: To attempt simplification of the constitution of a drive device, and facilitation of its maintenance and control by controlling feed and discharge of gas to and from a elastic contraction body which forces a driven member to carry out rotational or translational motion by means of a feeding and discharge means comprising a supply and discharge unit consisting of a switching valve and a flow rate control valve for a pressurization and discharge passage.

CONSTITUTION: Elastic contraction bodies 20a and 20b whose respective one-side ends are connected to a fixing member 12 are connected to respective ends of a chain 18 for driving a sprocket on one end of a support member 14 whose other end is fixed to the fixing member 12. On the other hand, the elastic contraction bodies 20a and 20b are driven by feeding and discharge means 24a and 24b of supply and discharge units 34a and 34b; 40a and 40b consisting of switching valves 30a and 30b; 36a and 36b, and flow rate control valves 32a and 32b; 38a and 38b for the purpose of intake and exhaust of gas from an operation pressure source 26 through a throttle valve 28. Consequently, a drive unit can be simplified and its maintenance and control can be facilitated, so that a space occupied for this purpose can be reduced.