PURPOSE: To prevent the breakage and disconnection of sign lamps by impact by a method in which a sign lamp is supported on a strut having a flexible part partly to ease impact to the sign lamp.

CONSTITUTION: A strut 1 is divided into an upper strut 1a and a lower strut 1b. When an impact acts on a sign lamp 2, the force point (b) of the impact is positioned at a distance L away from the support point (a) as the setting position of an elastic coil spring 3 to connect the struts 1a and 1b, and the rotary moment at the force point (b) to the support point (a) becomes greater and the inertia is increased. The impact to the lamp 2 is eased by the elastic part even when the rocking in every direction of the lamp 2 is great. Breakage and disconnection of the lamp 2 by impact can thus be prevented.