Abstract: An electric fuel pump for pumping a liquid fuel from a tank to an engine. The pump device has a regenerative pump section and an electric motor section for driving the regenerative pump section. The regenerative pump section includes a pump casing having a first inner surface and a second inner surface axially opposing to and spaced from each other to define therebetween a pump chamber, a shaft adapted to be rotatingly driven by the electric motor section and an impeller accommodated by the pump chamber and mounted on the shaft for rotation therewith but axially movably relatively thereto. The impeller has one axial end surface opposing to the first inner surface with a first gap formed therebetween, and the other axial end surface opposing to the second inner surface of the pump casing with a second gap formed therebetween.