Optical safety light curtain device that optically detects human intrusion into hazardous areas of industrial robots and automation equipment, enabling safe machine shutdown. Creates an invisible light curtain between transmitter and receiver to instantly detect worker hand or body intrusion. Installed around dangerous machinery such as press machines, injection molding machines, palletizers, and welding robots, providing high safety performance compliant with ISO13849 and JIS B 9705-1 safety standards. Unlike conventional safety fencing, ensures safety without compromising work efficiency in areas requiring frequent access. Available from high-function types with muting and blanking functions to simple single-beam types according to application needs.