A vehicle ventilation duct includes a duct body, a conduit, a sound
absorption chamber, a transmission opening communicating the conduit with
the sound absorption chamber, and an air-permeable member closing the
transmission opening permeably. The duct body is disposed in a vehicle
outer hull, and includes a frame having a ventilation opening opened to
the outside of a vehicle and a valve element covering the ventilation
opening openably and closably. The conduit is formed integrally with or
independently of the duct body, is disposed on a vehicle-passenger-room
side of the duct body, is communicated with the ventilation opening of
the duct body, and is communicated with the inside of a vehicle passenger
room, whereby enabling air inside and outside the vehicle to pass
therethrough back and forth. Thus, the ventilation duct lets out air in
the vehicle passenger room to the outside of the vehicle or vice versa.