A fastener for use in an electronic device includes a positioning unit and a clamping member. The positioning unit has a first supporting concave part allowing a first electronic device to be disposed, a fastening pin inserted in the positioning unit is disposed at a bottom end of clamping member, so that the bottom end of the clamping member enables the first electronic device to be in a locked status; the clamping member has a second supporting concave part allowing a second electronic device to be disposed, a chamber is at a location adjacent to one side of the second supporting concave part, and is connected to a sliding cover capable of radially and elastically sliding; with a front end of the sliding cover being released or be located above the second supporting concave part, the second electronic device can be in an unlocked status or a locked status.