A fuel pump improved in pump efficiency is provided. An impeller rotating in a pump casing has an approximately disk-shaped configuration with a group of recesses formed in a region extending along the outer peripheries of the obverse and reverse sides of the impeller. The recesses are repeatedly arranged in the circumferential direction at a distance between each pair of adjacent recesses. The radially outer end face of each recess slantingly extends radially outward from a middle plane in the direction of thickness toward the obverse and reverse sides. With this fuel pump, the incidence of separation or vortex formation in the flow of fuel is minimized, and a high pump efficiency can be obtained.