PURPOSE: To improve efficiency, by forming the insulation of a coil with inorganic material, and by filling up a frame with inert gas.

CONSTITUTION: An electromagnetic pump is organized by forming a duct 2 for a passage for circulating sodium liquid, with the internal pipe 1a and the external pipe 1b of a concentric double cylinder pipe 1, and by providing the external side of the external pipe 1b with a radial stator core 3. On the outer peripheral side of the stator core 3, a frame 5 is fitted, and into a pectinated- form slot 6 on the inner peripheral side, a ring-formed coil 7 is fitted. In this case, for the ring-formed coil 7, a copper system wire 10 expanded by inserting the heat-proof conductor 8 of the silver-containing copper or the like of a circular cross section into a seamless pipe 9 is used, and is organized with an insulation wire 12 forming a wire insulation 11 by winding up the outer periphery of the wire 10 with ceramic fiber or the like. Besides, fixed rings are butted to the both ends in the axial direction of the stator core 3, and the both ends are closed, and the frame 5 is filled up with the inert gas of argon gas or the like. Then, the whole unit can be used by dipping it in the sodium liquid of high temperature.