PURPOSE: To realize the installation in a narrow space by providing a hole for intercommunicating a container hole to an operation chamber on a rod side in the container hole formed in a piston member, and disposing, in a head cover, a supply pipe capable of sliding without any leak to the container hole and a pilot operating spool for changing over supply and exhaust of the operating chambers.

CONSTITUTION: There are provided in a piston member 2 a supply pipe 38 erected in a head cover 32 and a container hole 24 capable of sliding without any leak, and a hole 30 for intercommunicating the supply pipe 38 to an operation chamber 22 on a rod side is formed. In the head cover 32, there is provided a spool 66 driven by an actuator 95 which is actuated by a pilot fluid of supply and exhaust passages 92, 94, thus performing changeover of the operation chambers 22, 36 and supply and exhaust lines 60, 64, 66 of operating oil. Therefore, disposition of a pipeline, hose and the like around the cylinder can be eliminated, thus realizing the installation in a narrow space and increasing the number of cylinders to be installed.