Abstract: A laser security fence apparatus is disclosed for providing a warning signal in response to an intrusion by an intruder of a restricted area. The apparatus includes a laser generator for generating a laser beam and a first mirror aligned with the laser beam for reflecting the beam. A second mirror is aligned with the first mirror for reflecting the beam reflected by the first mirror and a collector is aligned with the second mirror for collecting the beam reflected by the second mirror. A microprocessor is associated with the collector and the generator for sensing when the beam is broken by the intruder so that the beam is not received by the collector. An alarm is connected to the microprocessor for actuation by the microprocessor when the microprocessor senses that the beam is broken so that the alarm provides the warning signal.