The present invention relates to an assembling structure of field coil, which has a simple mounting structure for a diode and a resistor to cut an off-noise of an electromagnetic clutch and to prevent damage of peripheral parts due to surge voltage generation when power source applied to an electronic coil body is cut off, thereby improving a mounting efficiency, reducing a manufacturing cost by reduction of the number of parts, and realizing an automatic production. The assembling structure of field coil includes an electronic coil body (101), a core ring (110) and a sleeve (120) having a first and second terminals (131) (132), and a case that has a receiving part (135) and a first and second connection parts (136) (137).