An inner cylinder inside an outer cylinder is disposed to be coaxial to an air pressure supply rod inside the inner cylinder. A first piston is disposed between the air pressure supply rod and the inner cylinder, a pneumatic chamber is disposed on a side of one surface (hydraulic surface) of the first piston in the inner cylinder, and a first hydraulic chamber is disposed on a side of the other surface. A second piston is disposed between the outer cylinder and the inner cylinder, and a second hydraulic chamber is disposed on a side of a surface of the second piston which is provided in the same direction as the hydraulic surface of the first piston in both of the cylinders. The inner cylinder is provided with a communication hole for transmitting a negative pressure along with movement of oil with which the first hydraulic chamber and the second hydraulic chamber are filled. In this configuration, it is possible to shorten an overall length of a fluid pressure cylinder.