To provide a rotor for a motor-driven pump advantageous to mass production and preventing the rust of the rotor.

When supporting an iron core 13 of a rotor body 10 by a positioning pin 29 to obtain an impeller molding by insert molding, a positioning hole 30a for secondary molding is formed by a pin 30, and in secondary molding, a positioning pin 35 serving as a second support member is inserted and supported in a recessed part 30A to perform secondary molding by insert molding. Plastic is thereby filled in a hole part 13A of the iron core 13 to cover an impeller 9 of the rotor 3 for the motor-driven pump double with a plastic layer.