<p>An ultra-thin USB female socket (1) comprises a metal upper housing (11), a metal lower housing (14), and an insulating body (13) with pin terminals (12) according to USB interface protocols. The pin terminals are fixed on the insulating body. The insulating body is fixed in the metal upper housing. The connection between the metal lower housing and the metal upper housing is a sliding connection with a changeable thickness. The thickness of the USB female socket is the thinnest when the metal upper housing mates with the metal lower housing entirely, thus the USB female socket can be used in an ultra-thin device; the thickness of the USB female socket is increased to the thickness of a standard USB female socket by pulling the metal lower housing outwards when the standard USB male socket is inserted into the USB female socket, thus the USB female socket can also be used in the standard USB male socket.</p>
