An opposed swash plate type fluid pressure rotating machine in which a first piston and a second piston projecting from opposite ends of a cylinder block reciprocate in a cylinder, respectively following a first swash plate and a second swash plate includes a center spring for biasing the cylinder block toward the second swash plate. A housing hole (biasing force receiving part) for receiving a biasing force of the center spring is formed on one end part of the cylinder block. The tip of a second neck (reaction force receiving part) for receiving a reaction force from the second swash plate is formed on the other end part of the cylinder block. The cylinder block is biased only toward the second swash plate by the center spring.