To provide a water-immersion and wire-breaking sensor cord which can detect both a water-immersion accident and a wire-breaking accident by itself with high precision without any misdetection, and to provide a cable for electric power, communications, etc., which is inexpensive and can bring about improved operation efficiency in laying operations when the water-immersion and wire-breaking sensor cord is incorporated and used.

One water-immersion and wire-breaking sensor cord 20 is incorporated between insulating cores 13 accommodated in a jacket sheath 14 of the cable 10. An expansion pressure press sheath 23 covering a water-absorptive swelling material 22 on an optical fiber 21 is molded into a high-rigidity cylinder by using a hard material such as HDPE to withstand the expansion pressure when the water-absorptive swelling material 22 increases in volume by absorbing rainwater. The expansion pressure operates as lateral pressure on the optical fiber 21 and light loss caused by backward scattered light and reflected light is detected. If the cable 10 is broken, light pulses incident on the optical fiber 21 of the water-immersion and wire-breaking sensor cord 20 are shut off as propagation is lost. A monitor detects that and the occurrence and place of the wire-breaking accident are confirmed.