A female screw member includes a female screw part with a female screw, and a projection part projecting in the direction of a center shaft of the female screw and having a working face in the rotating direction centering on the center shaft. The female screw part and projection part are integrally molded with a resin. The projection part has a spiral inclination face spirally inclining by one round from the working face centering on the center shaft of the female screw. The height H of the working face is equal to or smaller than a pitch P of the female screw. Using the projection part as a fully opening fixing stopper, a motor operated valve includes a valve main body having a valve seat, the female screw member attached to the valve main body, a motor having a rotator and stator, and a valve shaft. The valve shaft is screwed to a female screw of the female screw member, and is rotated and driven by the rotor, and has a fully opening movable stopper capable of contacting the fully opening fixing stopper.