FUEL TANK

A fuel tank is provided that has a carrier enhanced in rigidity and has a built-in component arranged with high accuracy. The fuel tank has a built-in component exclusively within an interior of a tank body, the built-in component including pillars and a carrier connecting between the pillars to present a ring shape in a planar view, wherein the carrier includes: outer extensions connecting between the pillars so as to form the ring shape; inner extensions extending inward of the ring shape from connection points between the outer extensions, and a coupling stand having the inner extensions joined thereto.