An adapter has a cylindrical body which is screwed onto a battery post, and a flange portion formed on a top portion of the cylindrical body to be clamped by a screwing tool. A terminal body includes a substantially U-shaped adaptor fitting portion which accommodates the adapter therein, and a seat portion on which an electric wire terminal is fixed. A lever includes a cam portion and is supported on the terminal body so as to be pivotable between a first position and a second position. A space in which the flange portion is capable of passing through is secured inside of the adaptor fitting portion when the lever is in the first position. The cam portion is abutted against an outer periphery of the cylindrical body of the adaptor so that the adaptor is retained between the cam portion and an inner face of the adaptor fitting portion, when the lever is in the second position. The flange portion of the adaptor is engaged with a top end face of the adapter fitting portion of the terminal body.