An electromagnet for use in a relay having a coil bobbin with flange portions at both ends of a coil winding portion where a coil is wound and an iron core with a flange-like head portion at one end of a body portion, the coil bobbin being so fitted onto the iron core that the flange-like head portion and the other end of the body portion of the iron core respectively project out of each of openings formed at the flange portions of the coil bobbin. The iron core has at the other end an engageable portion to be engaged with an engaging portion formed on a grasping part of a coil winding chuck device. The electromagnet further has between the coil bobbin and the iron core a means for preventing misregistration of the coil bobbin fitted onto the iron core.