Abstract: A multi-optical-path photoelectric safety apparatus or a light curtain is placed in front of a pressing machine or a folding machine. Optical paths are set as a floating blanking area B (some paths out of a large number of optical paths) in the light curtain. The operation of the pressing machine or folding machine is forcibly stopped when two contiguous optical paths are blocked in the floating blanking area B. On the other hand, the normal protection function serves in areas A and C between which area B is sandwiched. In these areas A and C, if any one optical path enters a light blocked state, the operation of the pressing machine or folding machine is immediately stopped.