Triple walled lamp

A lamp in which an inner bulb for containing a light emitting tube or a light emitting filament and an outer bulb for containing the inner bulb are attached coaxially to a base, and a spacer made of a thin metal sheet is attached to an exhaust tube protruded from a central region at the top end of the inner bulb for coaxially supporting the inner bulb to the outer bulb, wherein the spacer has a central plate formed with an aperture for allowing the exhaust tube to be inserted therethrough and having a plurality of fingers protruded inward along the inner periphery of the aperture, and three or more strips each branched radially outward from the central plate and formed in a curved shape for coaxially supporting the inner bulb to the outer bulb, and the exhaust tube is configured wider at the end on which the fingers of the spacer are held, as a stopper capable of inhibiting the movement of the fingers toward the top end of the exhaust tube, thereby preventing the central plate from dropping out of the exhaust tube.