Provided is a fuel tank made of resin, including: a fuel tank body that is enclosed by a bottom wall, side walls, and an upper wall, the fuel tank body including a first storage portion, a second storage portion, and a coupling portion, the coupling portion communicating an upper portion of the first storage portion and an upper portion of the second storage portion; a pump module disposed in the first storage portion; an open portion formed in the first storage portion; a strut provided in the first storage portion; a separator provided on the strut; a suction portion disposed in the second storage portion; a fuel transfer line that communicates the suction portion to the pump module; a holding portion and a provisional holding portion provided at the separator, the provisional holding portion being configured to removably hold the extra-length portion of the fuel transfer line.