PURPOSE: To prevent a careless and dangerous manual release operation and a loss of a handle by locking the handle to the non-manual release side with the manual release handle left over as is.

CONSTITUTION: The breaking device is equipped with an electric magnet 1, a breaking spring 2, a movable iron core 3, a breaking plate 4, a rotary disc 5, a center hub 6, and with a stud 9 so as to be enclosed by a cover 10. A place close to the outer circumference of the movable iron core 3 is pushed to be moved to the releasing side so as to be manually released by paired eccentric pins 11 which re rotated by a handle 12. A locking means 20 locking the handle 12 onto the cover 10 is made up of a handle receiver 21 which is fixed on the cover 10, and locks the handle 12 by a round section 21a in a J shape, and of a locking member 22 to be rotatably fitted in the handle 12. The locking member 22 is made up of a circular body 22a, bar-like body 22b which is integrated with the circular body 22a, can be disposed at the outside of the round section 21a, and is parallel with the handle 12, and of a screw 22c which is screwed in the opposite side in the circumferential direction of the round section 22b, so that the rocking member is threadedly fastened so as to be locked.