To provide an electro-hydraulic servo motor having a compact structure by devising the arrangement of a control valve.

This servomotor comprises a first helical gear 49 connected to an output shaft 34, second helical gears 52, 53 screw connected to a command rotary shaft of a pulse motor also meshed with the first helical gear 49 to be driven thereby, a spool valve energized by the second helical gear 52 so as to move therewith in accordance with changing of a rotational speed in one electric motor and the output shaft 34 to control a supply amount of operating oil to hydraulic drive means 37, 38, and another spool valve energized by the other second helical gear 53 so as to move therewith in accordance with changing of a rotational speed in a command rotary shaft of the other electric motor and the output shaft 34 to control a discharge amount of operating oil from the hydraulic drive means 37, 38.