Fuel pump

A fuel pump includes an impeller and a casing member. The impeller defines a plurality of vane grooves arranged in a circumferential direction. The casing member receives the impeller, and the casing member defines therein a pump passage configured to have an arcuate shape along the vane grooves. The discharge passage is provided downstream of the pressurizing passage. The discharge passage has a width narrower than a width of the pressurizing passage, and the discharge passage is positioned toward a radially outer wall of the pressurizing passage. The pressurizing passage includes a throttle part that extends from a starting point to an inlet of the discharge passage. The throttle part has a first width at the starting point, which corresponds to the width of the pressurizing passage, and a second width at the inlet, which corresponds to the width of the discharge passage.