PURPOSE: To suppress a foreign sound generated at separating gas and liquid without enlarging a vapor separator in a fuel tank for automobile having the vapor separator to be provided on the discharge hole of a return tube.

CONSTITUTION: In a fuel tank having such a constitution as supplying the fuel in a tank body 2 to an engine by a fuel pump 3 and returning excessive fuel to the tank body 2 through a return tube 6, a vapor separator 10 is provided on the discharge hole of the return tube 6. The vapor separator 10 is a box body having openings on both end parts and a vapor discharge hole formed on one end part, and arranged in such a manner that a gas-liquid separating part 10a for inserting the return tube 6 through one opening to receive the discharge hole in the box body is formed, a flat sectional fuel discharge part 10b including the other opening of the box body is formed, and the hollow part of the fuel discharge part 10b is vertically extended in the tank body 2.