<p>A projection (10c) is provided on a negative terminal (10) projecting toward the socket center and positioned directly below the bottom (13s) of the bulb base (13a), a cut-out recessed (10f) to the bottom is provided in the top of the base part (10e), which is positioned along the bottom of the bulb insertion opening (1a) and is bent in the perpendicular horizontal direction from the bottom of the flat member (10a), and the base part (10e) is set to not contact the positive terminal (11) when positioned with the projection (10c) contacting the bottom shoulder (13s) of the bulb base (13a). <IMAGE></p>
