To provide the mounting structure of a tube of a fuel tank for an automobile having satisfactory tube holding force with a simple structure by preventing interference between the peripheral component of the fuel tank and a tube mounting member.

In the mounting structure of the tube to be mounted on the fuel tank, a tube mounting member 20 is mounted on the outer wall 2 of the fuel tank, a tube 40 is inserted in the inner part of the tube mounting member 20 and an inner pipe 30 is inserted in the inner part of the tube 40 to mount the tube. A mounting flange part 25 and a tube mounting cylinder 22 are provided to the tube mounting member 20. The inside diameter of the tube mounting cylinder 22 is so formed that the root part 22 of the tube mounting cylinder is smaller than the tip end part 23 of the tube mounting cylinder. The outside diameter of the inner pipe 30 is so formed that the rear part 32 of the inner pipe is larger than the front part 31 of the inner pipe, so that the diameter of the tube tip part is expanded by the rear part 32 of the inner pipe and tube tip part is pressed to the tube mounting cylinder tip end part 23 and mounted.