A fuel tank in which it is possible to reduce working hours or cost in a manufacturing process and prevent an increase in weight in, a main wing, an aircraft fuselage, an aircraft, and a mobile body. The fuel tank is provided with a structural member using carbon fiber reinforced plastic in which a reinforcing material includes carbon fibers and a matrix includes plastic, wherein the matrix has electrical conductivity applied thereto. Furthermore, a cut surface of the structural member, which is formed by cutting the structural member, may be exposed to the inside in which fuel is accommodated, of a fuel tank.