A manufacturing method of an end plate of a pump that can remove a sag includes: punching a workpiece from a plate material, the workpiece being the end plate including a mounting seat including a fastener; forming a pressed trace surface by pressing an outer edge of an outer surface, when a surface, of both front and back surfaces of the punched workpiece, further from a sag formed on a cut end surface is the outer surface, and a surface, of both front and back surfaces of the punched workpiece, nearer to the sag is an inner surface. A section of the pressed trace surface disposed along an outer edge of the mounting seat is a fastening section. A section of the pressed trace surface other than the fastening section is a non-fastening section. A radial width of the fastening section is shorter than that of the non-fastening section.