FUEL TANK

A fuel tank enabled to enhance the rigidity thereof for mounting, to make the vibration frequency thereof higher than an unsprung vibration frequency, and to increase the durability thereof. In a fuel tank 1 in which a fuel tank body 10 is configured so that a flange 3b, 30b of an outer periphery of each separator 3, 30 is welded to an inner surface of a cross-sectionally substantially rectangular shaped cylindrical portion 2 and an end plate 4 is fixed to each of both opening end parts of the cylindrical portion 2, and the fuel tank body (10) is mounted on a substantially L-shaped bracket 6 attached to a side frame 5 and is fixed to the bracket 6 by winding a belt member 8 therearound, the separator 3, 30 is disposed just under the belt member 8, and a main bead 3e, 30e serving as a frame of the separator 3, 30 is provided in the separator 3, 30 to extend in a direction of a diagonal line from an upper corner portion 3c, 30c of the separator 3, 30 which is an input portion from which a tensile force of the belt member 8 is inputted, to a lower corner portion 3d, 30d of the separator 3, 30 at a corner portion 6a of the bracket 6. Also, both side edges of both ends of the main bead 3e, 30e are connected to the flange 3b, 30b through a curved surface 3f, 30f having a predetermined radius.