A hydraulic machine (7, 8) includes a rotation shaft (11), a cam (20) configured to rotate with the rotation shaft (11), a plurality of cylinders (22) disposed around the cam (20) each of which includes a distal end portion disposed on an outer side in a radial direction of the rotation shaft (11), a part of the distal end portion being formed by a first curved surface (23), a plurality of pistons (30) disposed around the cam (20) so that end portions of the pistons (30) at an inner side in the radial direction contact a cam surface (21) of the cam (20), the plurality of pistons (30) being configured to reciprocate in the cylinders (22) along a direction of a center axis of the cylinders (22) in accordance with rotation of the cam (20), a stationary member (40) disposed on an outer side of the cylinders (22) in the radial direction, the stationary member (40) including sockets (42) having second curved surfaces (43) which are engageable with the first curved surfaces (23) of the distal end portions of the cylinders (22), and at least one elastic member (60) for biasing the plurality of cylinders (22) outward in the radial direction so as to force the first curved surfaces (23) of the cylinders (22) against the second curved surfaces (43) of the sockets (42). The first curved surfaces (23) of the respective cylinders (22) engage with the second curved surfaces (43) of the sockets (42) so that rocking of each of the cylinders (22) is permitted at least in a plane perpendicular to a rotational axis of the rotation shaft (11).