Abstract: A device comprising a body with a sleeve slidably mounted thereon and attached to a blade which is slidably engaged ina longitudinal slot provided in the body and forming a sheath for said blade. A spring arranged within the sleeve between it and the body holds the blade in a retracted position inside the sheath. The projecting end of the body has four points for positioning the device relative to the needle to be threaded and the thread, and within range of a tip of the blade which may be "unsheathed" by manually moving the sleeve towards said points and said needle so that on the way it engages the thread between the points and leads it through the eye of the needle.