To secure insulating property between a case and an electromagnetic device by providing an air layer holding body having an air layer in its inside therebetween when housing the electromagnetic device in the case and filling a filler therebetween.

This electromagnetic device is provided with an air layer holding body 12 and a main body 13 thereof which are housed in a case 11 and a filler 14 filled therein. The case 11 is made of metal, and its one end has an opening 11a and the other end is closed and cylindrical. The air layer holding body 12 has a vinyl sheet 12a, on which a plurality of expanded sections 12c having air layers 12b in its inside on one side are provided. The main body 13 of the electromagnetic device is provided with a coil bobbin 22 wound by a coil 21 and an iron core 21, and terminals 24 are fitted to both ends of the coil bobbin 22 and lead wires 25 are connected with the terminals 24. Further, the air layer holding body 12 is interposed between the end faces of the case 11 and the main body 13 thereof, securing an insulating distance therebetween.