PURPOSE: To prevent the inflow of fog particles into the space on a road by providing a stricture section to a wind-receiving side, inducing an air current into an opening section while converging it, and sticking the fog particles on a windbreak board which is provided opposite the opening for an outlet and in the vicinity thereof.

CONSTITUTION: A wind receiving plate 2 has a V shaped section, a lengthwise slit-like opening section 5 is provided between adjacent wind receiving plates 2, and a stricture section 6 inducing an air-current into the opening section 5 is formed while converging it with each other's inclined wind receiving planes. A windbreak board 3 is so provided to an outlet side of the opening section 5 that it is opposite and adjacent to the opening section 5. When the air current including fog particles is applied to the wind receiving plates 2, it is accelerated to pass through the opening section 5 while converging it in the stricture section 6, and it is deflected by the windbreak board 3 to enter a space above a road. The fog particles having higher density in comparison with the deflected air current are stuck on the windbreak board 3. According to the constitution, fog particle removal efficiency can be promoted.