PURPOSE: To reduce the size of a product and to reduce a product cost by a method wherein the outside of a coil containing part for an electromagnetic coil to reciprocatively drive a pair of diaphragms is covered with a band formed approximately in a U-shape and a temperature-sensitive element connected in series to a coil is disposed on the outer surface of a coil.

CONSTITUTION: Annular plate-form plate cores 14 and 15 are arranged between the bobbins 10 and 11 of an electromagnetic coil 2 to reciprocatively drive a pair of the diaphragms 4 and 5 of an electromagnetic air pump 1. Further, plate cores 16 and 17 are arranged on the outer end faces of the bobbins 10 and 11. The cores 16 and 17 are formed in such a manner that an iron sheet is molded approximately in a U-shape through plates 20 and 21 arranged on the outer surfaces of the cores. Fastening and fixing are effected by means of a band 22 with which the upper surface and the two sides of a coil containing part 8 are covered. A temperature fuse 54 being a temperature-sensitive element is arranged at a connection corner part between the end part of a band 22 and a bottom plate 23 by utilizing the space of one corner part in the air pump 1 and fixed to the outer surface of the coil 13 by means of an adhesive.