A pilot stage for a jet type servo-valve, the pilot stage including an ejector for ejecting a jet of fluid and that is movable facing a deflector suitable for generating a pressure difference that can be used for moving a spool of the servo-valve. The ejector extends radially projecting from a column to which the ejector is secured and is in fluid-flow communication with a central bore of the column through which the ejector is fed with fluid, the column having a first end that is embedded in the servo-valve and through which the fluid is introduced into the column, and the column has a second end that is subjected to drive from a torque motor for selectively twisting the column in one direction or the other about a rest position.