To provide a duct capable of preventing external air from being sucked into a duct body from an opening of a sidewall, hardly causing clogging in a sound absorbing material, and capable of keeping excellent sound absorbing performance.

A hollow chamber 31 is formed on the outside surface of a sidewall 12 of a pipe-like duct body 11; the inside of the duct body 11 is separated from the hollow chamber 31 by a nonbreathable film body 21; the hollow chamber 31 uses a sound absorbing material 35 formed of a porous body for a part thereof in contact with the outside; the external air is prevented from being sucked into the duct body 11 from the opening 13 of the sidewall 12 by film body 21; clogging of the sound absorbing material 35 by suction of the external air into the duct body 11 from the opening 13 of the sidewall 12 is prevented; and thereby excellent sound absorbing performance can be kept.