Abstract: A rotary valve for changing the connections of the fluid inlet passages and the fluid outlet passages of a Gerotor type fluid rotary machine in which the fluid is contracted and expanded by a plurality of cavities defined by the teeth formed on a stator and a rotor in response to the orbital rotation of the rotor formed with one less external tooth than the number of the internal teeth on the stator. The rotary valve selectively connects the fluid passages with the Gerotor cavities by means of its rotary commutator which orbits with a phase difference of 90.degree. with respect to the Gerotor rotor, and the commutator is rotatably accommodated in a spacer disposed between an end cover and a port member having a plurality of fluid passages. The clearance at each side of the commutator is permanently determined by the width of the spacer.