To provide a fluid pressure machine (1) having at least one displacer chamber (6) in which liquid pressure medium (15), in particular, ion liquid is sealed.

A displacer chamber can be connected to an inlet passage (10) and an outlet passage (11) for the working fluid, and the liquid column of the liquid pressure medium (15) is interposed as the pressure transmitting medium between the working fluid in the displacer chamber and a displacer piston mechanism (17). In order to provide the fluid pressure machine having high displacement capacity in a slight structural occupied space, the displacer chamber (6) is provided inside a cylinder drum (5) rotating around the axial center (4), and the axial center of the displacer chamber is arranged toward the direction crossing the axial center (4) of the cylinder drum (5). Preferably, the displacer chamber (6) is provided within the cylinder drum (5) as a radial bore in the direction orthogonal to the axial center (4) of the cylinder drum (5).