A dual-plug adapter includes a casing defining an interior space. The casing forms a socket having a first and second slots for receiving an external plug. A circuit board is fixed in the interior space and includes first and second conductive members corresponding to the first and second slots of the socket for electrically engaging first and second blades of the external plug. First and second pairs of conductive, resilient leaves are formed on the circuit board and respectively and electrically connected to the first and second members. A plug portion is accommodated in the cavity, including a primary plug movably received in the cavity. The primary plug has first blades for engaging an external socket. The primary plug also has first conductive pads connected to the first blades. The primary plug is movable between a non-operative position and an operative position where the first conductive pads engage the first pair of conductive leaves of the circuit board. The plug portion also includes a secondary plug having second blades for engaging a different external socket. The secondary plug has second conductive pads electrically connected to the second blades. The secondary plug is movable between a non-operative position and an operative position.