An apparatus is provided for detecting a malfunction occurring in an electromagnetic brake of a robot. In the apparatus, the main relay and the sub-relay are controlled to open the main contact and the sub-contact when the robot is activated. Detecting is then made whether or not the main contact is malfunctioning, by monitoring an energized state of the main contact. Activation of the robot is stopped when the main contact is malfunctioning and the main relay is controlled to close the main contact for a given period of time when that the main contact is operating normally. Detecting is further made as to whether or not the sub-contact is malfunctioning, by monitoring an energized state of the sub-contact The activation of the robot is stopped when the sub-contact is malfunctioning and the main relay is controlled to close the main contact when the sub-contact is operating normally.