PURPOSE: To demagnetize the magnetization of the iron core and armature of an electromagnet by applying an electromagnetic brake to charge a capacitor when a switch element is turned on, and feeding the discharging current from the capacitor to a coil in the opposite direction when the switch element is turned off.

CONSTITUTION: When voltage is applied to the base terminal of a transistor Tr, the transistor Tr is turned on, the coil of the electromagnet of an electromagnetic brake device is excited, a brake is applied, and a capacitor is charged. When the voltage applied to the base terminal of the transistor Tr is stopped, the transistor Tr is turned off, a current flows in a loop of a coil L, the second resistor R2 and a diode D to be consumed, and the point 1' is returned to the reference potential Vcc. The reference potential of the capacitor C is raised by Vcc, the capacitor C is discharged, the discharging current is shunted to the coil L side and the second resistor R2 side, and a current flows in the coil L in the opposite direction to that when the transistor Tr is turned on. The magnetic force magnetized in the iron core 1 and armature 2 of the electromagnet is negated.