A cylinder apparatus comprises a piston which is displaced along a cylinder tube under the driving action of a driving section provided for a main cylinder body, while the piston is displaced under the pressing action of a pressure fluid supplied to the cylinder tube. The amount of the pressure fluid supplied to the main cylinder body is increased before a workpiece is engaged with a table section arranged at an end of the main cylinder body so that pressing force, which is applied to the piston, is increased. Accordingly, driving load, which is exerted on the driving section when the workpiece is engaged with the table section, is reduced.