A safety device for safeguarding a movable, guided movement element against undesired collisions with an object situated on a movement path of the movement element, said device comprising at least two sensors for detecting the object and the movement element and for outputting signals depending on the detection, and also having an evaluation unit for evaluating signals of the sensors and for generating a switch-off signal on the basis of the evaluation. For improved recognition of a risk of collision, the evaluation unit is designed to acquire from the at least two sensors a currently detected state vector from a set of state vectors which unambiguously comprise all possible combinations of the signals of the sensors, and to generate the switch-off signal in the case of predetermined state vectors.