In an overcurrent prevention system for a robot having links connected by joints and an electrical system including electric motors installed at the joint, a power circuit connecting the electric motors to a power source, and drive circuits to supply current to the electric motors, there are provided a switching device installed in the power circuit, a current sensor detecting the current supplied to the electric motors, and the output of the current sensor is compared with a threshold value and the switching device is operated to execute a switching action to cut off the power circuit intermittently during a first predetermined period when the output of the current sensor exceeds the threshold value, thereby protecting the electrical system when overcurrent is detected, without causing functional disablement and/or posture instability of the robot.