PURPOSE: To provide a pressure operated check valve to be inserted into a pneumatic circuit for accurately carrying out midway stoppage of a pneumatic cylinder.

CONSTITUTION: The pressure operated check valve is equipped with a valve body 4 of a check valve, a pushing piston 5 and a spring 6 for pushing up the piston 5. When there is pressure, the pushing piston 5 retreats and comes apart from the valve body 4. When there is no pressure, the pushing piston 5 moves forward and opens the valve body 4. Because pressure equal to the pneumatic pressure supplied is sealed in both a chamber 14 and a chamber 15 inside a pneumatic cylinder 13 by a pressure operated check valve, the pneumatic cylinder 13 can always be stopped at a constant position.