To provide a vent hood which can prevent surely dust from going into a room from the outside.

In a vent hood 5 used only for exhaust is provided with a body 6 which has a cylindrical exhaust port insertion section 9 which can be inserted into the exhaust port 4 of an exhaust duct 3 and is formed with a flange section 10 at one of its end, a cover 7, which is secured to the flange section 10 for preventing rain drops from going into the exhaust duct 3, a pair of right and left shutters 15, which is secured pivotally so as to be inclined freely to be able to close an exhaust flow passage properly, in an exhaust port insertion section 9, and a closing time stopper 24, which keeps each of the shutters 15 closed to the pressure of the wind from the outside B, the inclined shaft o of each shutter 15 is arranged so as to be extended vertically at a position near the sides of the shutters 15 which are adjacent to each other and so that the lower end of the inclined shaft o is offset to the outside B more than the upper end. Through such constitution, each of the shutters 15 can be closed due to their self weight when a pipe fan stops.