To improve productivity by a structure of a manual releasing lever in a shape free to form favorably in dimensional precision so as to comparatively easily assemble it.

An engagement part 14b to be inserted between an armature and a side plate 3 is provided on a manual releasing lever 11, a lower corner part on a surface opposed to the side plate 3 out of corner parts of the engagement part 14b is made a fulcrum to make contact with the side plate 3, and an upper corner part on a surface opposed to the armature is made an operating point to make contact with the armature. Additionally, falling of the manual releasing lever 11 is prevented by placing the engagement part 14b of the manual releasing lever 11 on a guide member. Furthermore, the manual releasing lever 11 is held by making a contact part 15 of the manual releasing lever 11 to contact on an outer peripheral surface of a field core.