A hydraulic servo device which controls the delivery of highpressure fluid in an amount proportional to a manual input signal including a rotary valve for supplying fluid to a rotary servo metering device that follows movement of the valve about the same axis delivering fluid to a remotely disposed actuator, with the servo metering device taking the form of a stationary internally toothed ring gear, a carrier supporting a plurality of planetary gears interengaging the stationary ring gear and defining therewith a plurality of expanding and contracting fluid chambers, there being provided in the rotary valve a supply port and two adjacent load ports which continuously communicate with the remote actuator for supplying fluid to and from the same, with a plurality of pressure-balancing recesses disposed oppositely in the rotary valve with respect to each of the ports in the valve, there being also provided two ports in the carrier for supplying fluid to and from the servo device so that the latter device acts in follow up action with respect to the rotary valve through the selective communication between the ports in the carrier and the supply port in the rotary valve. The rotary valve may be either of the closed center or open center type and may also be either load reactive or nonload reactive through the proper location of the load ports in the valve with respect to the two ports in the carrier member.