To provide a connecting structure of a pipe sleeve and a duct using the pipe sleeve, for improving the workability and reducing the labor and the cost.

The pipe sleeve 8 comprises a cylindrical sleeve body 9 and a flange part 12 fixed to an inner wall of the sleeve body 9. The pipe sleeve 8 is fixed onto a plate 2, and an opening is formed on an inner side with respect to an inner wall face of the sleeve body 9, of the plate 2. A part of the duct 6 comprising a duct main body 16 and a duct flange part 18 fixed to the duct main body 16 is inserted to the opening, and the duct flange part 18 is joined to the flange part 12 to connect the pipe sleeve 8 and the duct 6. The sleeve body 9 and the opening have sufficient inner diameters to permit the insertion of the duct 6 including the duct flange part 18, and the flange part 18 has a sufficient width to join the duct flange part 18.