Electromagnetic brake condition diagnosis device and method therefor

In an electromagnetic brake wherein braking force is generated by pressing a brake shoe against a brake drum by means of a spring, and a control voltage that is supplied to a brake coil of an electromagnet that attracts the brake shoe in resistance to the pressing force of the spring is controlled with a control unit, an electromagnetic brake condition diagnosis device that detects the drop-away starting current when the brake drops, and the attraction starting current when the brake is attracted, estimates the relationship between the pressing force and the brake stroke from the detected drop-away starting current, estimates the relationship between the attraction force of the electromagnet and the brake stroke from the detected attraction starting current, and uses the estimated relationship between the pressing force and the brake stroke and the estimated relationship between the attraction force and the brake stroke to detect the brake stroke and the pressing force.