An EL lamp comprises an EL light emitting part and a connector part which is connected to both electrodes of the EL light emitting part and is formed so as to be attachable to and detachable from a power supply outlet, and is a flat-­plate-shaped EL lamp having a reinforcement to give the EL lamp a mechanical tolerance endurable against the bending load applied in attaching and detaching the EL lamp to and from the outlet in a repeated manner, in a case where a portion of the EL lamp reinforced with said reinforcement is held by human fingers for attaching and detaching. Accordingly, the EL lamp in accordance with the present invention has quite new effects having not been obtained in the conventional EL lamps such that it is never broken heavily by an external force, can be used as a portable set, and is endurable enough against frequent attaching and detaching to and from the power supply outlet. In the using method of the present invention, an EL lamp is used together with a means capable of changing the illuminating direction of the EL lamp freely in desired directions, which brings about a comfortable use of the EL lamp. Specifically, it is extremely convenient if the EL lamp of the present invention is used for an automobile having an power supply outlet possessing an opening part with which a connector part of the EL lamp is engaged.