Abstract: A pierced earring includes a pin member provided midway thereof with an engaging groove, and a nut including a cylindrical fastener body having therein a split groove or slit extending in the direction of the length thereof, an engaging ridge formed on an inner peripheral surface thereof and a guide part tapering at one end of the fastener body. Intimate union between the engaging ridge of the cylindrical fastener body and the engaging groove of the pin member is attained by insertion of the pin member through the guide part into the cylindrical fastener body.