An electrically operated fuel pump apparatus comprises an electric motor and a regenerative pump having a pump housing and a disc-like impeller. The motor shaft has an end portion extending into a central axial through-hole formed in an end wall of the pump housing. A joint member comprising a ring-like base and a circumferential row of axial rods extending therefrom is rotatably disposed in the axial through-hole in the end wall of the pump housing and secured to the end portion of the motor shaft. The impeller is rotatably and axially movably mounted on an impeller shaft provided separately of the motor shaft and secured to the other end wall of the pump housing. The impeller is formed therein with a circumferential row of axial apertures with which the axial rods of the joint member loosely engage to transmit the rotation of the motor shaft to the impeller while permitting axial movement of the impeller relative to the motor shaft and the pump housing.