PURPOSE: To provide an iron core for a solenoid pump which can suppress extremely the electromagnetic vibration at the time of operation and prevents the dielectric breakdown of a coil due to the friction of a core tooth part with the coil.

CONSTITUTION: An iron core for a solenoid pump which is prepared by a method wherein an outer core tooth part 10 and an inner core tooth part 12 are formed by laminating ring-plate-shaped thin magnetic plates respectively, these tooth parts are made to engage with the outer circumference of an outer tube 2 and the inner circumference of an inner tube 1 alternately with an outer coil 9 and an inner coil 7, respectively, and the outer core tooth part 10 and the outer coil 9, and the inner core tooth part 12 and the inner coil 7, are tightened and integrated in the axial direction of the inner tube 1 and the outer tube 2 respectively.