A fuel pump includes an impeller and a cover. The impeller includes a ring portion, which is annular and is placed radially outward of blades. The cover has an arcuate pump flow passage. An enlarged space is formed in a cover side slide surface of the cover. The enlarged space is communicated with the pump flow passage and has an axial gap size, which is axially measured between an axial bottom surface of the enlarged space and an axial end surface of the ring portion and is larger than that of an axial slide gap between the slide surface and the axial end surface of the ring portion.