There is provided an air guide duct for a vehicle, the air guide duct connected for communication with an air conditioner unit provided in a passengers' room in a vehicle, the air guide duct adapted to pass and guide temperature regulated air supplied from the air conditioner unit, the air guide duct comprising a first base body constituting one duct half, the first base body including a mounting part for allowing a wire element of an electrical component system to be contained along the air guide duct, and a second base body constituting the other duct half, the second base body covered over the first base body to define an air flowing space therebetween, the second base body including a cover piece which laterally extends from the duct, wherein the mounting part containing the wire element is so constructed as to be covered with the cover piece.