PURPOSE: To suppress or to prevent generation of an abnormal sound by eliminating superposition of a pressure wave, from a sharp part in one object, on a reflected wave from a surface of the other object provided with a clearance from the sharp part.

CONSTITUTION: This structure prevents an abnormal sound by a wind passing through a clearance between a clearance lamp 20 having a sharp edge 21 in a part placed in the upstream of a wind A and a headlamp 24 having a surface 25 provided with a clearance 22 from the edge 21. The surface 25 of the headlamp has an irregular surface 28 formed so as to prevent a pressure wave, from the edge 21 of the clearance lamp, from being superposed on a reflected wave by the surface 25 of the pressure wave.