Abstract: An optical recording/reproducing apparatus includes an upper cover, a lower cover, and several vents. Each vent is arranged on the lower cover, and includes a first grille and a parallel second grille. The first and second grilles each include parallel louvers interleaved by parallel gaps. The first grille is arranged at an outer surface of the lower cover, while the second grille is arranged on an inner surface of the lower cover, with a clearance h separating the first and second grilles. Heat produced in the optical recording/reproducing apparatus is expelled out from the housing via the gaps of the second grille and the gaps of the first grille. However, external dust or contaminants that may enter the gaps of the first grille are blocked from entering the housing by the louvers of the second grille.