Abstract: An improved fastening device particularly adapted for hanging picture frames of the type provided with a channel section therein comprises an elongate, unitary element having intermediate portions thereof fashioned into a torsional spring which is inserted into the channel and grips portions of the latter without the need for anchoring screws. One extremity of the element extends longitudinally into the channel and abuts at least one sidewall thereof to prevent rotation of the device on the frame while the other extremity of the element projects out through an opening in the channel and has a hook member formed therein to allow attachment with a picture hanging wire.