Abstract: A safety device for an electromechanical opening and closing mechanism, such as an automotive sun roof, which interrupts a circuit for driving the mechanism when a load on the circuit happens to exceed a certain set value in an abnormal case such as when a foreign object is caught in the mechanism. The set value is either a first set value which varies in accordance with the above-noted load or a second set value which is determined by the position of the movable part of the above-noted mechanism. The safety device functions when a load exceeds either of the two set values. The first set value is effective against a load variation, particularly a load decrease, to prevent a decrease in sensitivity decrease of the safety device, while the second set value is effective against an increase in load, particularly a slow increase, to prevent an overload on the mechanism.